\(\left(x+12\right)+\left(x+45\right)+\left(x+88\right)+\left(x+55\right)=2200\)
Tìm số nguyên x :
\(\left\{-3x+2\left[45-x-3\left(3x+7\right)-2x\right]+4x\right\}=55-103-57:\left[-2\left(2x-1\right)^2-\left(-9\right)^0\right]=-106\)
Tìm số nguyên x
1/ \(17x+3\left(-16x-37\right)=2x+43-4x\)
2/ \(-2x-3\left(x-17\right)=34-2\left(-x+25\right)\)
3/ \(\left\{-3x+2\left[45-x-3\left(3x+7\right)-2x\right]+4x\right\}=55-103-57:\left[-2\left(2x-1\right)^2-\left(-9\right)^0\right]=-106\)
4/ \(-2x+3\left\{12-2\left[3x-\left(20+2x\right)-4x\right]+1\right\}=45\)
5/ \(3x-32>-5+1\)
6/ \(15+4x< 2x-145\)
7/ \(-3\left(2x+5\right)-16< -4\left(3-2x\right)\)
8/ \(-2x+15< 3x-7< 19-x\)
bài tập tết nâng cao phải ko
mk cũng có nhưng chưa làm dc
\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+\left(x+4\right)+\left(x+5\right)=55\)
=> \(5x+1+2+3+4+5=55\)
=> \(5x=55-15=40\)
=> \(x=8\)
(x+1) + (x+2)+(x+3)+(x+4)+(x+5)=55
=> 5x + 15=55
=>5x=55-15=40
=>x=40/5
Vây x= 8
x + 1 + x + 2 + x + 3 + x + 4 + x + 5 = 55
( x+x+x+x+x)+(1+2+3+4+5)=55
5x +15 = 55
=> 5x = 55 - 15 = 40
=> x = 40 : 5
x = 8
Vậy x = 8
Rút gọn
\(\frac{x^3-53x+88}{\left(x-1\right)\left(x-3\right)\left(x-5\right)\left(x-7\right)+16}\)
Tìm x biết :
a) \(\left(x-2\right)^3+6\left(x+1\right)^2-x^3+12=0\)
b) \(\left(x-5\right)\left(x+5\right)-\left(x+3\right)^3+3\left(x-2\right)^2=\left(x+1\right)^2-\left(x+4\right)\left(x-4\right)+3x^2\)
c) \(\left(2x+3\right)^2+\left(x-1\right)\left(x+1\right)=5\left(x+2\right)^2-\left(x-5\right)\left(x+1\right)+\left(x+4\right)^2\)
d) \(\left(1-3x\right)^2-\left(x-2\right)\left(9x+1\right)=\left(3x-4\right)\left(3x+4\right)-9\left(x+3\right)^2\)
a/ \(x=\dfrac{-5}{12}\)
b/ \(x\approx-1,9526\)
c/ \(x=\dfrac{21-i\sqrt{199}}{10}\)
d/ \(x=\dfrac{-20}{13}\)
a) (x-2)3+6(x+1)2-x3+12=0
⇒ x3-6x2+12x-8+6(x2+2x+1)-x3+12=0
⇒ x3-6x2+12x-8+6x2+12x+6-x3+12=0
⇒ 24x+10=0
⇒ 24x=-10
⇒ x=-5/12
a.
PT \(\Leftrightarrow x^3-6x^2+12x-8+6(x^2+2x+1)-x^3+12=0\)
\(\Leftrightarrow x^3-6x^2+12x-8+6x^2+12x+6-x^3+12=0\)
\(\Leftrightarrow 24x+10=0\Leftrightarrow x=\frac{-5}{12}\)
b. Bạn xem lại đề, nghiệm khá xấu không phù hợp với mức độ tổng thể của bài.
c.
PT $\Leftrightarrow (4x^2+12x+9)+(x^2-1)=5(x^2+4x+4)+(x^2-4x-5)+9(x^2+6x+9)$
$\Leftrightarrow 10x^2+42x+64=0$
$\Leftrightarrow x^2+(3x+7)^2=-15< 0$ (vô lý)
Do đó pt vô nghiệm.
d.
PT $\Leftrightarrow (1-6x+9x^2)-(9x^2-17x-2)=(9x^2-16)-9(x^2+6x+9)$
$\Leftrightarrow 11x+3=-54x-97$
$\Leftrightarrow 65x=-100$
$\Leftrightarrow x=\frac{-20}{13}$
PHÂN TÍCH:
a) \(\left(x+2\right)\left(x-4\right)\left(x+6\right)\left(x-12\right)+36x^2\)
b) \(4\left(x+5\right)\left(x+6\right)\left(x+10\right)\left(x+12\right)-3x^2\)
c) \(\left(x-18\right)\left(x-7\right)\left(x+35\right)\left(x+90\right)-67x^2\)
Làm 1 câu các câu còn lại tương tự!
a, \(\left(x+2\right)\left(x-4\right)\left(x+6\right)\left(x-12\right)+36x^2\)
\(=\left[\left(x+2\right)\left(x-12\right)\right]\left[\left(x-4\right)\left(x+6\right)\right]+36x^2\)
\(=\left(x^2-12x+2x-24\right)\left(x^2+6x-4x-24\right)+36x^2\)
\(=\left(x^2-10x-24\right)\left(x^2+2x-24\right)+36x^2\)(1)
Đặt \(a=x^2-10x-24\Rightarrow a+12x=x^2+2x-24\)
\(\Rightarrow\left(1\right)=a\left(a+12x\right)+36x^2=a^2+12ax+36x^2\)
\(=a^2+6ax+6ax+36x^2=a\left(a+6x\right)+6x\left(a+6x\right)\)
\(=\left(a+6x\right)^2\)(*)
Vì \(a=x^2-10x-24\) nên
(*)\(=\left(x^2-10x-24+6x\right)^2=\left(x^2-4x-24\right)^2\)
Vậy...........
Rút gọn :
\(\dfrac{\sqrt{x+\sqrt{4\left(x-1\right)}}-\sqrt{x-\sqrt{4\left(x-1\right)}}}{\sqrt{x^2-4\left(x-1\right)}}.\left(\sqrt{x-1}-\dfrac{1}{\sqrt{x-1}}\right)\)
b)\(\left(\sqrt{2}+1\right)\left(\sqrt{3}+1\right)\left(\sqrt{6}+1\right)\left(5-2\sqrt{2}-\sqrt{3}\right)\)
c)\(\left(\sqrt{5}+1\right)\left(\sqrt{7}+1\right)\left(\sqrt{35}+1\right)\left(34-4\sqrt{7}-6\sqrt{5}\right)\)
d) \(\left(\sqrt{7}+1\right)\left(2\sqrt{2}-1\right)\left(2\sqrt{14}-1\right)\left(55+12\sqrt{2}-7\sqrt{7}\right)\)
e)\(\left(3\sqrt{2}+1\right)\left(2\sqrt{3}+1\right)\left(6\sqrt{6}+1\right)\left(215-34\sqrt{3}-33\sqrt{2}\right)\)
Tìm \(x\):
\(8\)) \(1-\left(x-6\right)=4\left(2-2x\right)\)
\(9\))\(\left(3x-2\right)\left(x+5\right)=0\)
\(10\))\(\left(x+3\right)\left(x^2+2\right)=0\)
\(11\))\(\left(5x-1\right)\left(x^2-9\right)=0\)
\(12\))\(x\left(x-3\right)+3\left(x-3\right)=0\)
\(13\))\(x\left(x-5\right)-4x+20=0\)
\(14\))\(x^2+4x-5=0\)
\(8,1-\left(x-6\right)=4\left(2-2x\right)\)
\(\Leftrightarrow1-x+6=8-8x\)
\(\Leftrightarrow-x+8x=8-1-6\)
\(\Leftrightarrow7x=1\)
\(\Leftrightarrow x=\dfrac{1}{7}\)
\(9,\left(3x-2\right)\left(x+5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}3x-2=0\\x+5=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{2}{3}\\x=-5\end{matrix}\right.\)
\(10,\left(x+3\right)\left(x^2+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+3=0\\x^2+2=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-3\\x=\varnothing\end{matrix}\right.\)
`8)1-(x-5)=4(2-2x)`
`<=>1-x+5=8-6x`
`<=>5x=2<=>x=2/5`
`9)(3x-2)(x+5)=0`
`<=>[(x=2/3),(x=-5):}`
`10)(x+3)(x^2+2)=0`
Mà `x^2+2 > 0 AA x`
`=>x+3=0`
`<=>x=-3`
`11)(5x-1)(x^2-9)=0`
`<=>(5x-1)(x-3)(x+3)=0`
`<=>[(x=1/5),(x=3),(x=-3):}`
`12)x(x-3)+3(x-3)=0`
`<=>(x-3)(x+3)=0`
`<=>[(x=3),(x=-3):}`
`13)x(x-5)-4x+20=0`
`<=>x(x-5)-4(x-5)=0`
`<=>(x-5)(x-4)=0`
`<=>[(x=5),(x=4):}`
`14)x^2+4x-5=0`
`<=>x^2+5x-x-5=0`
`<=>(x+5)(x-1)=0`
`<=>[(x=-5),(x=1):}`
\(11,=>\left[{}\begin{matrix}5x-1=0\\x^2-9=0\end{matrix}\right.=>\left[{}\begin{matrix}x=\dfrac{1}{5}\\x=3\\x=-3\end{matrix}\right.\\ 12,=>\left(x+3\right)\left(x-3\right)=0\\ =>\left[{}\begin{matrix}x+3=0\\x-3=0\end{matrix}\right.=>\left[{}\begin{matrix}x=-3\\x=3\end{matrix}\right.\\ 13,=>x\left(x-5\right)-4\left(x-5\right)=0\\ =>\left(x-4\right)\left(x-5\right)=0\\ =>\left[{}\begin{matrix}x-4=0\\x-5=0\end{matrix}\right.=>\left[{}\begin{matrix}x=4\\x=5\end{matrix}\right.\)
\(14,=>x^2+5x-x-5=0\\ =>x\left(x+5\right)-\left(x+5\right)=0\\ =>\left(x-1\right)\left(x+5\right)=0\\ =>\left[{}\begin{matrix}x-1=0\\x+5=0\end{matrix}\right.=>\left[{}\begin{matrix}x=1\\x=-5\end{matrix}\right.\)
1) Đa thức\(\left(x^2+x+1\right)\left(X^2+x+2\right)\)-12 được phân tích thành nhân tử là:
A)\(\left(x^2+x+5\right)\left(x+2\right)\left(x-1\right)\)
B)\(\left(x^2+x-5\right)\left(x+2\right)\left(x-1\right)\)
C)\(\left(x^2-x+5\right)\left(x+2\right)\left(x-1\right)\)
D)\(\left(x^2+x+5\right)\left(x-2\right)\left(x+1\right)\)
2) \(\left(x+a\right)\left(x+2a\right)\left(x+3a\right)\left(x+4a\right)+a^4\) được phân tích thành nhân tử là:
A)\(\left(x^2+5ax-5a^2\right)\left(x^2-5ax+5a^2\right)\)
B)\(\left(x^2-5ax-5a^2\right)\left(x^2+5ax+5a^2\right)\)
C)\(\left(x^2-5ax-5a^2\right)\left(x^2-5ax+5a^2\right)\)
D)\(\left(x^2+5ax+5a^2\right)^{^2}\)
3) Đa thức \(a^3+b^3+c^3-3abc\) được phân tích thành nhân tử là:
A)\(\left(a+b+c\right)\left(a^2+b^2+c^2-ab+bc-ca\right)\)
B)\(\left(a-b+c\right)\left(a^2+b^2+c^2-ab-bc-ca\right)\)
C)\(\left(a+b+c\right)\left(a^2+b^2+c^2-ab-bc-ca\right)\)
D)\(\left(a+b+c\right)\left(a^2+b^2+c^2-ab+bc-ca\right)\)
4) Đa thức x(x+1)(x+2)(x+3)+1 được phân tích thành nhân tử là:
A)\(\left(x^2+3x+1\right)\left(x^2+3x-1\right)\)
B)\(\left(x^2+3x+1\right)^{^2}\)
C)\(\left(x^2+3x+1\right)\left(x^2-3x+1\right)\)
D) Cả B và C đều sai
5) Câu trả lời đúng cho M=\(n^2\left(n+1\right)+2n\left(n+1\right)+360\) với \(n\in Z\)
A)M⋮4
B)M⋮5
C)M⋮6
D)M⋮9
6)Cho \(P=\left(2n+5\right)^{^2}-145\) với \(n\in N\)
A) P⋮4 ; B)P⋮3 ; C) P⋮5 ; D)P⋮6
7) Giá trị của biểu thức \(x^2-y^2-2y-1\) tại
x=502 ; y=497 là:
A) 3000
B)5000
C)4500
D) cả A và B đều sai
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