\(\left\{{}\begin{matrix}x^2+y^2+x+y=8\\x^2+y^2+2x-3y=1\end{matrix}\right.\)
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hệ phương trình
1 ,left{{}begin{matrix}frac{2x-3}{2y-5}frac{3x+1}{3y-4}2left(x-3right)-3left(y+2right)-16end{matrix}right.
2, left{{}begin{matrix}frac{x}{y}frac{3}{2}3x-2y5end{matrix}right.
3, left{{}begin{matrix}frac{x^2-y-6}{x}x-2x+3y8end{matrix}right.
4, left{{}begin{matrix}frac{x}{y}frac{2}{3}x+y10end{matrix}right.
5, left{{}begin{matrix}frac{y^2+2x-8}{y}y-3x+y10end{matrix}right.
6 , left{{}begin{matrix}frac{x+1}{y-1}53left(2x-2right)-4left(3x+4right)5end{matrix}right.
7, left{{}begi...
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hệ phương trình
1 ,\(\left\{{}\begin{matrix}\frac{2x-3}{2y-5}=\frac{3x+1}{3y-4}\\2\left(x-3\right)-3\left(y+2\right)=-16\end{matrix}\right.\)
2, \(\left\{{}\begin{matrix}\frac{x}{y}=\frac{3}{2}\\3x-2y=5\end{matrix}\right.\)
3, \(\left\{{}\begin{matrix}\frac{x^2-y-6}{x}=x-2\\x+3y=8\end{matrix}\right.\)
4, \(\left\{{}\begin{matrix}\frac{x}{y}=\frac{2}{3}\\x+y=10\end{matrix}\right.\)
5, \(\left\{{}\begin{matrix}\frac{y^2+2x-8}{y}=y-3\\x+y=10\end{matrix}\right.\)
6 , \(\left\{{}\begin{matrix}\frac{x+1}{y-1}=5\\3\left(2x-2\right)-4\left(3x+4\right)=5\end{matrix}\right.\)
7, \(\left\{{}\begin{matrix}2x+y=4\\\left|x-2y\right|=3\end{matrix}\right.\)
8 , \(\left\{{}\begin{matrix}\frac{2x}{x+1}+\frac{y}{y+1}=3\\\frac{x}{x+1}-\frac{3y}{y+1}=-1\end{matrix}\right.\)
9 , \(\left\{{}\begin{matrix}y-\left|x\right|=1\\2x-y=1\end{matrix}\right.\)
10 , \(\left\{{}\begin{matrix}\sqrt{x+3y}=\sqrt{3x-1}\\5x-y=9\end{matrix}\right.\)
mọi người giải gúp mình với. Cần cực gấp a,left{{}begin{matrix}3x+2y-2-x+4y3end{matrix}right.b,left{{}begin{matrix}x+2y115x-3y3end{matrix}right.c,left{{}begin{matrix}10x-9y115x+21y36end{matrix}right.d,left{{}begin{matrix}2x+y3x+y2end{matrix}right.e,left{{}begin{matrix}x+y22x-3y9end{matrix}right.f,left{{}begin{matrix}x-2y115x+3y3end{matrix}right.g,left{{}begin{matrix}3x-y52x+3y18end{matrix}right.h,left{{}begin{matrix}5x+3y-73x-y-8end{matrix}right.
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mọi người giải gúp mình với. Cần cực gấp \(a,\left\{{}\begin{matrix}3x+2y=-2\\-x+4y=3\end{matrix}\right.b,\left\{{}\begin{matrix}x+2y=11\\5x-3y=3\end{matrix}\right.c,\left\{{}\begin{matrix}10x-9y=1\\15x+21y=36\end{matrix}\right.d,\left\{{}\begin{matrix}2x+y=3\\x+y=2\end{matrix}\right.e,\left\{{}\begin{matrix}x+y=2\\2x-3y=9\end{matrix}\right.f,\left\{{}\begin{matrix}x-2y=11\\5x+3y=3\end{matrix}\right.g,\left\{{}\begin{matrix}3x-y=5\\2x+3y=18\end{matrix}\right.h,\left\{{}\begin{matrix}5x+3y=-7\\3x-y=-8\end{matrix}\right.\)
a, Ta có : \(\left\{{}\begin{matrix}3x+2y=-2\\-x+4y=3\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}3\left(4y-3\right)+2y=-2\\x=4y-3\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}12y-9+2y=-2\\x=4y-3\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}14y=7\\x=4y-3\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}y=\frac{1}{2}\\x=\frac{4.1}{2}-3=-1\end{matrix}\right.\)
Vậy hệ phương trình có duy nhất 1 nghiệm là \(\left(x;y\right)=\left(-1;\frac{1}{2}\right)\)
b, Ta có : \(\left\{{}\begin{matrix}x+2y=11\\5x-3y=3\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}x=11-2y\\5\left(11-2y\right)-3y=3\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}x=11-2y\\55-10y-3y=3\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}x=11-2y\\-13y=-52\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}x=11-2.4=3\\y=4\end{matrix}\right.\)
Vậy hệ phương trình có duy nhất 1 nghiệm là \(\left(x;y\right)=\left(3;4\right)\)
c, Ta có : \(\left\{{}\begin{matrix}10x-9y=1\\15x+21y=36\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}30x-27y=3\\30x+42y=72\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}10x-9y=1\\-69y=-69\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}10x-9=1\\y=1\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}x=1\\y=1\end{matrix}\right.\)
Vậy hệ phương trình có duy nhất 1 nghiệm là \(\left(x;y\right)=\left(1;1\right)\)
d, Ta có : \(\left\{{}\begin{matrix}2x+y=3\\x+y=2\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}y=3-2x\\x+2-2x=2\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}y=3-2x\\2-x=2\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}y=3-2.0=3\\x=0\end{matrix}\right.\)
Vậy hệ phương trình có duy nhất 1 nghiệm là \(\left(x;y\right)=\left(0;3\right)\)
e, Ta có : \(\left\{{}\begin{matrix}x+y=2\\2x-3y=9\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}x=2-y\\2\left(2-y\right)-3y=9\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}x=2-y\\4-2y-3y=9\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}x=2-y\\-5y=5\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}x=2+1=3\\y=-1\end{matrix}\right.\)
Vậy hệ phương trình có duy nhất 1 nghiệm là \(\left(x;y\right)=\left(3;-1\right)\)
f, Ta có : \(\left\{{}\begin{matrix}x-2y=11\\5x+3y=3\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}x=11+2y\\5\left(11+2y\right)+3y=3\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}x=11+2y\\55+10y+3y=3\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}x=11+2y\\13y=-52\end{matrix}\right.\)
Vậy hệ phương trình có duy nhất 1 nghiệm là \(\left(x;y\right)=\left(3;-4\right)\)
g, Ta có : \(\left\{{}\begin{matrix}3x-y=5\\2x+3y=18\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}y=3x-5\\2x+3\left(3x-5\right)=18\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}y=3x-5\\2x+9x-15=18\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}y=3x-5\\11x=33\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}y=9-5=4\\x=3\end{matrix}\right.\)
Vậy hệ phương trình có duy nhất 1 nghiệm là \(\left(x;y\right)=\left(3;4\right)\)
h, Ta có : \(\left\{{}\begin{matrix}5x+3y=-7\\3x-y=-8\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}5x+3\left(3x+8\right)=-7\\y=3x+8\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}5x+9x+24=-7\\y=3x+8\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}14x=-31\\y=3x+8\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}x=-\frac{31}{14}\\y=3.\left(-\frac{31}{14}\right)+8=\frac{19}{14}\end{matrix}\right.\)
Vậy hệ phương trình có duy nhất 1 nghiệm là \(\left(x;y\right)=\left(-\frac{31}{14};\frac{19}{14}\right)\)
giải hệ pt bằng phương pháp thế:1) left{{}begin{matrix}x+y3x+2y5end{matrix}right.2) left{{}begin{matrix}x-y3y2x+1end{matrix}right.3) left{{}begin{matrix}2x+3y4y-x-2end{matrix}right.4) left{{}begin{matrix}xy+2x3y+8end{matrix}right.5) left{{}begin{matrix}2x-y13x-4y2end{matrix}right.giúp mk vs ạ mai mk hc rồi
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giải hệ pt bằng phương pháp thế:
1) \(\left\{{}\begin{matrix}x+y=3\\x+2y=5\end{matrix}\right.\)
2) \(\left\{{}\begin{matrix}x-y=3\\y=2x+1\end{matrix}\right.\)
3) \(\left\{{}\begin{matrix}2x+3y=4\\y-x=-2\end{matrix}\right.\)
4) \(\left\{{}\begin{matrix}x=y+2\\x=3y+8\end{matrix}\right.\)
5) \(\left\{{}\begin{matrix}2x-y=1\\3x-4y=2\end{matrix}\right.\)
giúp mk vs ạ mai mk hc rồi
\(1,\Leftrightarrow\left\{{}\begin{matrix}x=3-y\\3-y+2y=5\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=3-y\\y=2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=1\\y=2\end{matrix}\right.\\ 2,\Leftrightarrow\left\{{}\begin{matrix}x-2x-1=3\\y=2x+1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-2\\y=2\left(-2\right)+1=-3\end{matrix}\right.\\ 3,\Leftrightarrow\left\{{}\begin{matrix}2x+3x-6=4\\y=x-2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=2\\y=0\end{matrix}\right.\\ 4,\Leftrightarrow\left\{{}\begin{matrix}x=y+2\\y+2=3y+8\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=y+2\\y=-3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-1\\y=-3\end{matrix}\right.\\ 5,\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{1+y}{2}\\\dfrac{3+3y}{2}-4y=2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{1+y}{2}\\3+3y-8y=4\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{y+1}{2}\\y=-\dfrac{1}{5}\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{2}{5}\\y=-\dfrac{1}{5}\end{matrix}\right.\)
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Giải hệ phương trình:a) left{{}begin{matrix}sqrt{3y^2+13}-sqrt{15-2x}sqrt{x+1}y^4-2x^2y+7y^2left(x+1right)left(8-xright)end{matrix}right.b) left{{}begin{matrix}sqrt{x+y}-sqrt{x-y}2sqrt{x^2+y^2+1}-sqrt{x^2-y^2}3end{matrix}right.c) left{{}begin{matrix}sqrt{2x+y+1}-sqrt{x+y}3sqrt{3left(x+yright)^2+1}+sqrt{x-5}5end{matrix}right.
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Giải hệ phương trình:
a) \(\left\{{}\begin{matrix}\sqrt{3y^2+13}-\sqrt{15-2x}=\sqrt{x+1}\\y^4-2x^2y+7y^2=\left(x+1\right)\left(8-x\right)\end{matrix}\right.\)
b) \(\left\{{}\begin{matrix}\sqrt{x+y}-\sqrt{x-y}=2\\\sqrt{x^2+y^2+1}-\sqrt{x^2-y^2}=3\end{matrix}\right.\)
c) \(\left\{{}\begin{matrix}\sqrt{2x+y+1}-\sqrt{x+y}=3\\\sqrt{3\left(x+y\right)^2+1}+\sqrt{x-5}=5\end{matrix}\right.\)
1)left{{}begin{matrix}2x+dfrac{1}{y}dfrac{3}{x}2y+dfrac{1}{x}dfrac{3}{y}end{matrix}right.2)left{{}begin{matrix}x^33x+8yy^33y+8xend{matrix}right.3)left{{}begin{matrix}x^2+y^2+x-2y2x^2+y^2+2x+2y11end{matrix}right.4)left{{}begin{matrix}x^3-y13x^2-3xy+y^21end{matrix}right.5)left{{}begin{matrix}x^3-y^39left(x-yright)left(x^2+y^2right)15end{matrix}right.
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1)\(\left\{{}\begin{matrix}2x+\dfrac{1}{y}=\dfrac{3}{x}\\2y+\dfrac{1}{x}=\dfrac{3}{y}\end{matrix}\right.\)
2)\(\left\{{}\begin{matrix}x^3=3x+8y\\y^3=3y+8x\end{matrix}\right.\)
3)\(\left\{{}\begin{matrix}x^2+y^2+x-2y=2\\x^2+y^2+2x+2y=11\end{matrix}\right.\)
4)\(\left\{{}\begin{matrix}x^3-y=1\\3x^2-3xy+y^2=1\end{matrix}\right.\)
5)\(\left\{{}\begin{matrix}x^3-y^3=9\\\left(x-y\right)\left(x^2+y^2\right)=15\end{matrix}\right.\)
a)left{{}begin{matrix}2left|x-6right|+3left|y-1right|55left|x-6right|-4left|y+1right|1end{matrix}right.
b) left{{}begin{matrix}2left|x+yright|-left|x-yright|93left|x+yright|+2left|x-yright|+17end{matrix}right.
c)left{{}begin{matrix}4left|x+yright|+3left|x-yright|83left|x+yright|-5left|x-yright|6end{matrix}right.
d) left{{}begin{matrix}x^2-xy242x-3y1end{matrix}right.
e) left{{}begin{matrix}3x-4y+10xy3left(x+yright)-9end{matrix}right.
f) left{{}begin{matrix}2x+3y53x^2-y^2+2y4end{matrix}right.
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a)\(\left\{{}\begin{matrix}2\left|x-6\right|+3\left|y-1\right|=5\\5\left|x-6\right|-4\left|y+1\right|=1\end{matrix}\right.\)
b) \(\left\{{}\begin{matrix}2\left|x+y\right|-\left|x-y\right|=9\\3\left|x+y\right|+2\left|x-y\right|+17\end{matrix}\right.\)
c)\(\left\{{}\begin{matrix}4\left|x+y\right|+3\left|x-y\right|=8\\3\left|x+y\right|-5\left|x-y\right|=6\end{matrix}\right.\)
d) \(\left\{{}\begin{matrix}x^2-xy=24\\2x-3y=1\end{matrix}\right.\)
e) \(\left\{{}\begin{matrix}3x-4y+1=0\\xy=3\left(x+y\right)-9\end{matrix}\right.\)
f) \(\left\{{}\begin{matrix}2x+3y=5\\3x^2-y^2+2y=4\end{matrix}\right.\)
a: Đặt |x-6|=a, |y+1|=b
Theo đề, ta có hệ phương trình:
\(\left\{{}\begin{matrix}2a+3b=5\\5a-4b=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=1\\b=1\end{matrix}\right.\)
=>|x-6|=1 và |y+1|=1
\(\Leftrightarrow\left\{{}\begin{matrix}x\in\left\{7;5\right\}\\y\in\left\{0;-2\right\}\end{matrix}\right.\)
b: Đặt |x+y|=a, |x-y|=b
Theo đề, ta có: \(\left\{{}\begin{matrix}2a-b=19\\3a+2b=17\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=\dfrac{55}{7}\\b=-\dfrac{23}{7}\left(loại\right)\end{matrix}\right.\)
=>HPTVN
c: Đặt |x+y|=a, |x-y|=b
Theo đề ta có: \(\left\{{}\begin{matrix}4a+3b=8\\3a-5b=6\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=2\\b=0\end{matrix}\right.\)
=>|x+y|=2 và x=y
=>|2x|=2 và x=y
=>x=y=1 hoặc x=y=-1
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hệ phương trình
1, left{{}begin{matrix}frac{1}{x+y}+frac{1}{x-y}frac{5}{8}frac{1}{x+y}-frac{1}{x-y}-frac{3}{8}end{matrix}right.
2, left{{}begin{matrix}frac{4}{2x-3y}+frac{5}{3x+y}2frac{3}{3x+y}-frac{5}{2x-3y}21end{matrix}right.
3, left{{}begin{matrix}frac{7}{x-y+2}+frac{5}{x+y-1}frac{9}{2}frac{3}{x-y+2}+frac{2}{x+y-1}4end{matrix}right.
4, left{{}begin{matrix}frac{3}{x}+frac{5}{y}-frac{3}{2}frac{5}{x}-frac{2}{y}frac{8}{3}end{matrix}right.
5 , left{{}begin{matrix}frac{2}{x+y-1}-frac{4}{x-y+1...
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hệ phương trình
1, \(\left\{{}\begin{matrix}\frac{1}{x+y}+\frac{1}{x-y}=\frac{5}{8}\\\frac{1}{x+y}-\frac{1}{x-y}=-\frac{3}{8}\end{matrix}\right.\)
2, \(\left\{{}\begin{matrix}\frac{4}{2x-3y}+\frac{5}{3x+y}=2\\\frac{3}{3x+y}-\frac{5}{2x-3y}=21\end{matrix}\right.\)
3, \(\left\{{}\begin{matrix}\frac{7}{x-y+2}+\frac{5}{x+y-1}=\frac{9}{2}\\\frac{3}{x-y+2}+\frac{2}{x+y-1}=4\end{matrix}\right.\)
4, \(\left\{{}\begin{matrix}\frac{3}{x}+\frac{5}{y}=-\frac{3}{2}\\\frac{5}{x}-\frac{2}{y}=\frac{8}{3}\end{matrix}\right.\)
5 , \(\left\{{}\begin{matrix}\frac{2}{x+y-1}-\frac{4}{x-y+1}=-\frac{14}{5}\\\frac{3}{x+y-1}+\frac{2}{x-y+1}=-\frac{13}{5}\end{matrix}\right.\)
6 , \(\left\{{}\frac{\frac{2x-3}{2y-5}=\frac{3x+1}{3y-4}}{2\left(x-3\right)-3\left(y+20=-16\right)}}\)
7\(\left\{{}\begin{matrix}\left(x+3\right)\left(y+5\right)=\left(x+1\right)\left(y+8\right)\\\left(2x-3\right)\left(5y+7\right)=2\left(5x-6\right)\left(y+1\right)\end{matrix}\right.\)
giải hệ phương trình
1, left{{}begin{matrix}2x^2+3y173x^2-2y6end{matrix}right.
2, left{{}begin{matrix}left|x-1right|+left|y-1right|24left|x-1right|+3left|y-1right|7end{matrix}right.
3, left{{}begin{matrix}3sqrt{x-1}+2sqrt{y}22sqrt{x-1}-sqrt{y}4end{matrix}right.
4 , left{{}begin{matrix}x+y2left|2x-3yright|1end{matrix}right.
5 , left{{}begin{matrix}2x-y1left|x-yright|left|2y-1right|end{matrix}right.
6,left{{}begin{matrix}left(x-3right)left(y+6right)xyleft(x+2right)left(y-2right)xyend{matrix...
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giải hệ phương trình
1, \(\left\{{}\begin{matrix}2x^2+3y=17\\3x^2-2y=6\end{matrix}\right.\)
2, \(\left\{{}\begin{matrix}\left|x-1\right|+\left|y-1\right|=2\\4\left|x-1\right|+3\left|y-1\right|=7\end{matrix}\right.\)
3, \(\left\{{}\begin{matrix}3\sqrt{x-1}+2\sqrt{y}=2\\2\sqrt{x-1}-\sqrt{y}=4\end{matrix}\right.\)
4 , \(\left\{{}\begin{matrix}x+y=2\\\left|2x-3y\right|=1\end{matrix}\right.\)
5 , \(\left\{{}\begin{matrix}2x-y=1\\\left|x-y\right|=\left|2y-1\right|\end{matrix}\right.\)
6,\(\left\{{}\begin{matrix}\left(x-3\right)\left(y+6\right)=xy\\\left(x+2\right)\left(y-2\right)=xy\end{matrix}\right.\)
7 , \(\left\{{}\begin{matrix}\left(x-3\right)\left(2y+5\right)=\left(2x+7\right)\left(y-1\right)\\\left(4x+1\right)\left(3y-6\right)=\left(6x-1\right)\left(2y+3\right)\end{matrix}\right.\)
8 , \(\left\{{}\begin{matrix}4x^2-5\left(y+1\right)=\left(2x-3\right)^2\\3\left(7x+2\right)=5\left(2y-1\right)-3x\end{matrix}\right.\)
giải hpt:
a) \(\left\{{}\begin{matrix}4x+9y=6\\3x^2+6xy-x+3y=0\end{matrix}\right.\)
b) \(\left\{{}\begin{matrix}\left(x+y+2\right)\left(2x+2y-1\right)=0\\3x^2-32y^2+5=0\end{matrix}\right.\)
c) \(\left\{{}\begin{matrix}2x^2-xy+3y^2=7x+12y-1\\x-y+1=0\end{matrix}\right.\)
Giải phương trình bằng phương pháp thế :
1) left{{}begin{matrix}4x+y28x+3y5end{matrix}right.
2) left{{}begin{matrix}x-ym2x+y4end{matrix}right.
3)left{{}begin{matrix}3x+2y6x-y2end{matrix}right.
4) left{{}begin{matrix}2x-3y1-4x+6y2end{matrix}right.
5)left{{}begin{matrix}2x+3y55x-4y1end{matrix}right.
6)left{{}begin{matrix}3x-y7x+2y0end{matrix}right.
7)left{{}begin{matrix}x+4y23x+2y4end{matrix}right.
8)left{{}begin{matrix}-x-y2-2x-3y9end{matrix}right.
9)left{{...
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Giải phương trình bằng phương pháp thế :
1) \(\left\{{}\begin{matrix}4x+y=2\\8x+3y=5\end{matrix}\right.\)
2) \(\left\{{}\begin{matrix}x-y=m\\2x+y=4\end{matrix}\right.\)
3)\(\left\{{}\begin{matrix}3x+2y=6\\x-y=2\end{matrix}\right.\)
4) \(\left\{{}\begin{matrix}2x-3y=1\\-4x+6y=2\end{matrix}\right.\)
5)\(\left\{{}\begin{matrix}2x+3y=5\\5x-4y=1\end{matrix}\right.\)
6)\(\left\{{}\begin{matrix}3x-y=7\\x+2y=0\end{matrix}\right.\)
7)\(\left\{{}\begin{matrix}x+4y=2\\3x+2y=4\end{matrix}\right.\)
8)\(\left\{{}\begin{matrix}-x-y=2\\-2x-3y=9\end{matrix}\right.\)
9)\(\left\{{}\begin{matrix}2x-3y=2\\-4x+6y=2\end{matrix}\right.\)
giúp mình với :((
1) \(\left\{{}\begin{matrix}4x+y=2\\8x+3y=5\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}y=2-4x\\8x+3\left(2-4x\right)=5\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x=\frac{1}{4}\\y=1\end{matrix}\right.\)
2) 2 pt 3 ẩn không giải được.
3) \(\left\{{}\begin{matrix}3x+2y=6\\x-y=2\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}y=x-2\\3x+2\left(x-2\right)=6\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}x=2\\y=0\end{matrix}\right.\)
4) \(\left\{{}\begin{matrix}2x-3y=1\\-4x+6y=2\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}x=\frac{3y+1}{2}\\-4\cdot\frac{3y+1}{2}+6y=2\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}y=\varnothing\\x=\varnothing\end{matrix}\right.\)
5) \(\left\{{}\begin{matrix}2x+3y=5\\5x-4y=1\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}x=\frac{-3y+5}{2}\\5\cdot\frac{-3y+5}{2}-4y=1\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}y=1\\x=1\end{matrix}\right.\)
6) \(\left\{{}\begin{matrix}3x-y=7\\x+2y=0\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}y=3x-7\\x+2\left(3x-7\right)=0\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}x=2\\y=-1\end{matrix}\right.\)
7) \(\left\{{}\begin{matrix}x+4y=2\\3x+2y=4\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}x=2-4y\\3\left(2-4y\right)+2y=4\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}y=\frac{1}{5}\\x=\frac{6}{5}\end{matrix}\right.\)
8) \(\left\{{}\begin{matrix}-x-y=2\\-2x-3y=9\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}y=-x-2\\-2x-3\left(-x-2\right)=9\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}x=3\\y=-5\end{matrix}\right.\)
9) \(\left\{{}\begin{matrix}2x-3y=2\\-4x+6y=2\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}x=\frac{3y+2}{2}\\-4\cdot\frac{3y+2}{2}+6y=2\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}y=\varnothing\\x=\varnothing\end{matrix}\right.\)