\(\left\{{}\begin{matrix}x2-y\left[x+y\right]+1=0\\\left[x2+1\right]\left[x+y-2\right]+y=0\end{matrix}\right.\)
1,\(\left\{{}\begin{matrix}x^2+xy-3x+y=0\\x^4+3x^2y-5x^2+y^2=0\end{matrix}\right.\)
2, \(\left\{{}\begin{matrix}\left(2x-1\right)^2+4\left(y-1\right)^2=22\\xy\left(x-1\right)\left(y-2\right)=1\end{matrix}\right.\)
3, \(\left\{{}\begin{matrix}\left(x^2+y^2\right)\left(x+y+1\right)=25\left(y+1\right)\\x^2+xy+2y^2+x-8y=9\end{matrix}\right.\)
4,\(\left\{{}\begin{matrix}5x^2y-4xy^2+3y^2-2\left(x+y\right)=0\\xy\left(x^2+y^2\right)+2=\left(x+y\right)^2\end{matrix}\right.\)
giải hệ pt :
a,\(\left\{{}\begin{matrix}x^3y\left(1+y\right)+x^2y^2\left(2+y\right)+xy^3-30=0\\x^2y+x\left(1+y+y^2\right)+y-11=0\end{matrix}\right.\)
b,\(\left\{{}\begin{matrix}xy^2-2y+3x^2=0\\y^2+x^2y+2x=0\end{matrix}\right.\)
c,\(\left\{{}\begin{matrix}3xy+2y=5\\2xy\left(x+y\right)+y^2=5\end{matrix}\right.\)
\(\left\{{}\begin{matrix}x^3y^2+x^2y^3+x^3y+2x^2y^2+xy^3-30=0\\x^2y+xy^2+xy+x+y-11=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x^2y^2\left(x+y\right)+xy\left(x+y\right)^2-30=0\\xy\left(x+y\right)+xy+x+y-11=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}xy\left(x+y\right)\left[xy+x+y\right]-30=0\\xy\left(x+y\right)+xy+x+y-11=0\end{matrix}\right.\)
Đặt \(\left\{{}\begin{matrix}xy\left(x+y\right)=u\\xy+x+y=v\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}uv-30=0\\u+v-11=0\end{matrix}\right.\) \(\Rightarrow\left(u;v\right)=\left(6;5\right);\left(5;6\right)\)
TH1: \(\left\{{}\begin{matrix}xy\left(x+y\right)=6\\xy+x+y=5\end{matrix}\right.\)
Theo Viet đảo \(\Rightarrow\left\{{}\begin{matrix}x+y=3\\xy=2\end{matrix}\right.\) \(\Rightarrow\left(x;y\right)=\left(1;2\right);\left(2;1\right)\)hoặc \(\left\{{}\begin{matrix}x+y=2\\xy=3\end{matrix}\right.\)(vô nghiệm)
TH2: \(\left\{{}\begin{matrix}xy\left(x+y\right)=5\\xy+x+y=6\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}x+y=5\\xy=1\end{matrix}\right.\) \(\Rightarrow...\) hoặc \(\left\{{}\begin{matrix}x+y=1\\xy=5\end{matrix}\right.\) (vô nghiệm)
2 câu dưới hình như em hỏi rồi?
Giải hệ phương trình
a)\(\left\{{}\begin{matrix}6x^2-3xy+x=1-y\\x^2+y^2=1\end{matrix}\right.\) c)\(\left\{{}\begin{matrix}\left|x+1\right|+\left|y-1\right|=5\\\left|x+1\right|-4y+4=0\end{matrix}\right.\)
b)\(\left\{{}\begin{matrix}2x^2-2x+xy-y=0\\x^2-3xy+4=0\end{matrix}\right.\)
a \(\Leftrightarrow\left\{{}\begin{matrix}6x^2-3xy+x=1-y\left(1\right)\\x^2+y^2=1\left(2\right)\end{matrix}\right.\) Từ (1) \(\Rightarrow6x^2-3xy+x-1+y=0\)
\(\Leftrightarrow\left(6x^2+x-1\right)-\left(3xy-y\right)=0\) \(\Leftrightarrow\left(6x^2+3x-2x-1\right)+y\left(3x-1\right)=0\)
\(\Leftrightarrow\left(3x-1\right)\left(2x+1\right)+y\left(3x-1\right)=0\) \(\Leftrightarrow\left(3x-1\right)\left(2x+1+y\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}3x-1=0\\2x+y=-1\end{matrix}\right.\)
*Nếu 3x-1=0⇔x=\(\dfrac{1}{3}\) Thay vào (2) ta được:
\(\dfrac{1}{9}+y^2=1\Leftrightarrow y^2=\dfrac{8}{9}\Leftrightarrow y=\dfrac{\pm2\sqrt{2}}{3}\)
*Nếu 2x+y=-1\(\Leftrightarrow y=-1-2x\) Thay vào (2) ta được :
\(\Rightarrow x^2+\left(-2x-1\right)^2=1\Leftrightarrow x^2+4x^2+4x+1=1\Leftrightarrow5x^2+4x=0\Leftrightarrow x\left(5x+4\right)=0\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{-4}{5}\end{matrix}\right.\)
.Nếu x=0⇒y=0
.Nếu x=\(\dfrac{-4}{5}\) \(\Rightarrow y=-1+\dfrac{4}{5}=-\dfrac{1}{5}\) Vậy...
Câu b)
\(\left\{{}\begin{matrix}2x^2-2x+xy-y=0\\x^2-3xy+4=0\end{matrix}\right.\)
⇔\(\left\{{}\begin{matrix}2x\left(x-1\right)+y\left(x-1\right)\\x^2-3xy+4=0\end{matrix}\right.\)
⇔\(\left\{{}\begin{matrix}\left(x-1\right)\left(2x+y\right)=0\\x^2-3xy+4=0\left(2\right)\end{matrix}\right.\)
Để (x-1)(2x+y) = 0 thì: \(\left[{}\begin{matrix}x-1=0\\2x+y=0\end{matrix}\right.\)⇔\(\left[{}\begin{matrix}x=1\\2x+y=0\end{matrix}\right.\)
Thay x=1 vào PT (2) ta có:
(2) ⇔12-3.1.y+4=0
⇔1-3y +4=0
⇔-3y+5=0
⇔y=\(\dfrac{5}{3}\)
Vậy HPT có nghiệm (x:y) = (1;\(\dfrac{5}{3}\))
b\(\left\{{}\begin{matrix}2x^2-2x+xy-y=0\left(1\right)\\x^2-3xy+4=0\left(2\right)\end{matrix}\right.\)
Từ (1) \(\Rightarrow2x\left(x-1\right)+y\left(x-1\right)=0\Leftrightarrow\left(x-1\right)\left(2x+y\right)=0\Leftrightarrow\left[{}\begin{matrix}x-1=0\\2x+y=0\end{matrix}\right.\)
*Nếu x-1=0⇔x=1 Thay vào (2) ta được: \(1-3y+4=0\Leftrightarrow3y=5\Leftrightarrow y=\dfrac{5}{3}\)
*Nếu 2x+y=0\(\Leftrightarrow y=-2x\) Thay vào (2) ta được:
\(\Rightarrow x^2+6x^2+4=0\Leftrightarrow7x^2=-4\) Vô lí ⇒ Trường hợp này ko có x,y (L)
Vậy...
(1)\(\left\{{}\begin{matrix}x^2+y^2=5\\xy\left(x^2-y^2\right)=6\end{matrix}\right.\)
(2)\(\left\{{}\begin{matrix}x^2+y^2+xy=18\\xy\left(x+2y\right)\left(y-x\right)=72\end{matrix}\right.\)
(3)\(\left\{{}\begin{matrix}x\left(x+y+1\right)-3=0\\\left(x+y\right)^2-\dfrac{5}{x^2}+1=0\end{matrix}\right.\)
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
Ghpt:
a) \(\left\{{}\begin{matrix}\left(4x^2+1\right).x+\left(y-3\right)\sqrt{5-2y}=0\\4x^2+y^2+2\sqrt{3-4x}=7\end{matrix}\right.\)
b) \(\left\{{}\begin{matrix}x^2+y^2=5\\\sqrt{y-1}\left(x+y-1\right)=\left(y-2\right)\sqrt{x+y}\end{matrix}\right.\)
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 hệ
a) \(\left\{{}\begin{matrix}x^2\left(y^2+1\right)+2y\left(x^2+x+1\right)=3\\\left(x^2+x\right)\left(y^2+y\right)=1\end{matrix}\right.\)
b) \(\left\{{}\begin{matrix}\left(6x+5\right)\sqrt{2x+1}-2y-3y^3=0\\y+\sqrt{x}=\sqrt{2x^2+4x-23}\end{matrix}\right.\)
Giải bất pt
\(\dfrac{9}{\left|x-5\right|-3}\ge\left|x-2\right|\)
1)\(\left\{{}\begin{matrix}x^2-y^2-2x+2y=0\\x^2-3xy+5y^2-3=0\end{matrix}\right.\)
2)\(\left\{{}\begin{matrix}\frac{1}{x}+\frac{1}{1-y}=1\\\frac{1}{x-1}-\frac{1}{y}=2\end{matrix}\right.\)
3)\(\left\{{}\begin{matrix}x^2-4x+3=0\\x^2+xy+y^2=1\end{matrix}\right.\)
4)\(\left\{{}\begin{matrix}x^2+y^2+x+y=2\\\left(x+1\right)^2-\left(y+2\right)^2=0\end{matrix}\right.\)
ai giải giúp mik với, mik cần gấp lắm