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8 tháng 7 2021

\(\left(x^2+4\right)^2-16x^2=x^4+8x^2+16-16x^2=x^4-8x^2+16=\left(x^2-4\right)^2=\left[\left(x-2\right)\left(x+2\right)\right]^2\)

Câu 1:  x2 + 2 xy + y2   bằng:A. x2 + y2                   B.(x + y)2                  C. y2 – x2                  D. x2 – y2Câu 2:  (4x + 2)(4x – 2)  bằng:A. 4x2 + 4                  B. 4x2 – 4                 C. 16x2 + 4                D. 16x2 – 4Câu 3: 25a2  + 9b2  - 30ab  bằng:A.(5a-9b)2                  B.(5a – 3b)2              C.(5a+3b)2                D.(5a)2 – (3b)2Câu 4: 8x3 +1 bằngA.(2x+1).(4x2-2x+1)      B. (2x-1).(4x2+2x+1)       C.(2x+1)3            D.(2x)3-13Câu 5:Thực...
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Câu 1:  x2 + 2 xy + y2   bằng:

A. x2 + y2                   B.(x + y)2                  C. y2 – x2                  D. x2 – y2

Câu 2:  (4x + 2)(4x – 2)  bằng:

A. 4x2 + 4                  B. 4x2 – 4                 C. 16x2 + 4                D. 16x2 – 4

Câu 3: 25a2  + 9b- 30ab  bằng:

A.(5a-9b)2                  B.(5a – 3b)2              C.(5a+3b)2                D.(5a)2 – (3b)2

Câu 4: 8x3 +1 bằng

A.(2x+1).(4x2-2x+1)      B. (2x-1).(4x2+2x+1)       C.(2x+1)3            D.(2x)3-13

Câu 5:Thực hiện phép nhân  x(3x2 + 2x - 5) ta được:

A.3x3 - 2x2 – 5x          B. 3x3 + 2x2 – 5x      C. 3x3 - 2x2 +5x         D. 3x3 + 2x2 + 5x

2
23 tháng 11 2021

câu 1 B 

câu 2 D

câu 3 ko bt 

câu 4 x=-1/2; x = -(căn bậc hai(3)*i-1)/4;x = (căn bậc hai(3)*i+1)/4;

câu 5 x=-5/3, x=0, x=1

23 tháng 11 2021

Câu 1:  x2 + 2 xy + y2   bằng:

A. x+ y2                   B.(x + y)2                  C. y2 – x2                  D. x2 – y2

Câu 2:  (4x + 2)(4x – 2)  bằng:

A. 4x2 + 4                  B. 4x2 – 4                 C. 16x2 + 4                D. 16x2 – 4

Câu 3: 25a2  + 9b2  - 30ab  bằng:

A.(5a-9b)2                  B.(5a – 3b)2              C.(5a+3b)2                D.(5a)2 – (3b)2

Câu 4: 8x3 +1 bằng

A.(2x+1).(4x2-2x+1)      B. (2x-1).(4x2+2x+1)       C.(2x+1)3            D.(2x)3-13

Câu 5:Thực hiện phép nhân  x(3x2 + 2x - 5) ta được:

A.3x- 2x– 5x          B. 3x+ 2x– 5x      C. 3x- 2x+5x         D. 3x+ 2x+ 5x

27 tháng 8 2021

\(\left(x-y\right)^2-4=\left(x-y-2\right)\left(x-y+2\right)\)

\(9-\left(x-y\right)^2=\left(3-x+y\right)\left(3+x-y\right)\)

\(\left(x^2+4\right)^2-16x^2=\left(x^2-4x+4\right)\left(x^2+4x+4\right)=\left(x-2\right)^2\left(x+2\right)^2\)

27 tháng 8 2021

\((X-y)^2-4=(x-y-2)(x-y+2)\)\((X^2+4)^2-16x^2=(x^2+4)^2-(4x)^2=(x^2+4-4x)(x^2+4+4x)\)

\(9-(x-y)^2=(3-x+y)(3+x-y)\)

 

8 tháng 8 2023

`4-x=2(x-4)^2`

`<=>4-x=2(x^2-8x+16)`

`<=> 4-x=2x^2 - 16x+32`

`<=> 4-x-2x^2+16x-32=0`

`<=> -2x^2 +15x-28=0`

`<=> -(2x^2-15x+28)=0`

`<=>-(2x^2-7x-8x+28)=0`

`<=> - [x(2x-7) - 4(2x-7)]=0`

`<=> -(2x-7)(x-4)=0`

\(\Leftrightarrow\left[{}\begin{matrix}-2x+7=0\\x-4=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}-2x=-7\\x=4\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{7}{2}\\x=4\end{matrix}\right.\)

__

`(x^2 +1) (x-2)+2x=4`

`<=> x^3 -2x^2 +x-2+2x-4=0`

`<=> x^3 -2x^2 +3x-6=0`

`<=> (x^3+3x)-(2x^2+6)=0`

`<=> x(x^2 +3) -2(x^2+3)=0`

`<=>(x^2+3)(x-2)=0`

\(\Leftrightarrow\left[{}\begin{matrix}x^2+3=0\\x-2=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x\in\varnothing\\x=2\end{matrix}\right.\)

__

`x^4 -16x^2=0`

`<=> x^2 (x^2 -16)=0`

`<=>x^2(x-4)(x+4)=0`

\(\Leftrightarrow\left[{}\begin{matrix}x^2=0\\x-4=0\\x+4=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=4\\x=-4\end{matrix}\right.\)

8 tháng 8 2023

\(4-x=2\left(x-4\right)^2\)

\(\Leftrightarrow4-x=2\left(x^2-8x+16\right)\)

\(\Leftrightarrow4-x=2x^2-16x+32\)

\(\Leftrightarrow2x^2-15x+28=0\)

\(\Leftrightarrow2x^2-7x-8x+28=0\)

\(\Leftrightarrow x\left(2x-7\right)-4\left(2x-7\right)=0\)

\(\Leftrightarrow\left(2x-7\right)\left(x-4\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}2x-7\\x=4\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{7}{2}\\x=4\end{matrix}\right.\)

___________

\(\left(x^2+1\right)\left(x-2\right)+2x=4\)

\(\Leftrightarrow x^3-2x^2+x-2+2x=4\)

\(\Leftrightarrow x^3-2x^2+3x-2-4=0\)

\(\Leftrightarrow x^3-2x^2+3x-6=0\)

\(\Leftrightarrow x^2\left(x-2\right)+3\left(x-2\right)=0\)

\(\Leftrightarrow\left(x^2+3\right)\left(x-2\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x^2=-3\left(\text{vô lý}\right)\\x=2\left(tm\right)\end{matrix}\right.\)

\(\Leftrightarrow x=2\)

________________

\(x^4-16x^2=0\)

\(\Leftrightarrow\left(x^2\right)^2-\left(4x\right)^2=0\)

\(\Leftrightarrow\left(x^2-4x\right)\left(x^2+4x\right)=0\)

\(\Leftrightarrow x\left(x-4\right)x\left(x+4\right)=0\)

\(\Leftrightarrow x^2\left(x-4\right)\left(x+4\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x^2=0\\x-4=0\\x+4=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=4\\x=-4\end{matrix}\right.\)

10 tháng 10 2021

\(6x^3-9x^2=3x^2\left(2x-3\right)\\ 25x^2-0,09=\left(5x-0,3\right)\left(5x+0,3\right)\\ x^2-x-y^2-y=\left(x-y\right)\left(x+y\right)-\left(x+y\right)=\left(x+y\right)\left(x-y-1\right)\\ \left(x^2+4\right)^2-16x^2=\left(x^2-4x+4\right)\left(x^2+4x+4\right)=\left(x-2\right)^2\left(x+2\right)^2\)

22 tháng 8 2023

a) \(4x^2-1\)

\(=\left(2x\right)^2-1^2\)

\(=\left(2x-1\right)\left(2x+1\right)\)

b) \(x^2-3y^2\)

\(=x^2-\left(y\sqrt{3}\right)^2\)

\(=\left(x-y\sqrt{3}\right)\left(x+y\sqrt{3}\right)\)

c) \(9x^2-\dfrac{1}{4}\)

\(=\left(3x\right)^2-\left(\dfrac{1}{2}\right)^2\)

\(=\left(3x-\dfrac{1}{2}\right)\left(3x+\dfrac{1}{2}\right)\)

d) \(\left(x-y\right)^2-4\)

\(=\left(x-y\right)^2-2^2\)

\(=\left(x-y-2\right)\left(x-y+2\right)\)

e) \(9-\left(x-y\right)^2\)

\(=3^2-\left(x-y\right)^2\)

\(=\left(3+x-y\right)\left(3-x+y\right)\)

f) \(\left(x^2+4\right)^2-16x^2\)

\(=\left(x^2+4\right)^2-\left(4x\right)^2\)

\(=\left(x^2-4x+4\right)\left(x^2+4x+4\right)\)

\(=\left(x-2\right)^2\left(x+2\right)^2\)

9 tháng 1 2022

\(a,4x^2-4y^2-20x+20y=4\left(x^2-y^2\right)-\left(20x-20y\right)=4\left(x-y\right)\left(x+y\right)-20\left(x-y\right)=\left(x-y\right)\left(4x+4y-20\right)=4\left(x-y\right)\left(x+y-5\right)\\ b,16x^2-25+\left(4x-5\right)=\left(4x-5\right)\left(4x+5\right)+\left(4x-5\right)=\left(4x-5\right)\left(4x+5+1\right)=\left(4x-5\right)\left(4x+6\right)=2\left(4x-5\right)\left(2x+3\right)\)

\(c,\left(x+5y\right)^3=x^3+15x^2y+75xy^2+125y^3\\ e,x^2-4x+4-y^2=\left(x-2\right)^2-y^2=\left(x-y-2\right)\left(x+y-2\right)\\ g,x^2-3x-4=\left(x^2-4x\right)+\left(x-4\right)=x\left(x-4\right)+\left(x-4\right)=\left(x+1\right)\left(x-4\right)\)

23 tháng 10 2021

\(a,\Leftrightarrow\left(x-2\right)\left(3x-1\right)=0\Leftrightarrow\left[{}\begin{matrix}x=2\\x=\dfrac{1}{3}\end{matrix}\right.\\ b,\Leftrightarrow\left(x-2\right)^3=0\Leftrightarrow x-2=0\Leftrightarrow x=2\\ c,\Leftrightarrow\left(4x-3x-3\right)\left(4x+3x+3\right)=0\\ \Leftrightarrow\left(x-3\right)\left(7x+3\right)=0\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-\dfrac{3}{7}\end{matrix}\right.\\ d,\Leftrightarrow x^2\left(x-1\right)-4\left(x-1\right)^2=0\\ \Leftrightarrow\left(x-1\right)\left(x^2-4x+4\right)=0\\ \Leftrightarrow\left(x-1\right)\left(x-2\right)^2=0\Leftrightarrow\left[{}\begin{matrix}x=1\\x=2\end{matrix}\right.\)

26 tháng 9 2023

 \(a,4x^2-1\)

\(=\left(2x\right)^2-1^2\)

\(=\left(2x-1\right)\left(2x+1\right)\)

\(b,25x^2-0,09\)

\(=\left(5x\right)^2-\left(0,3\right)^2\)

\(=\left(5x-0,3\right)\left(5x+0,3\right)\)

\(d,\left(x-y\right)^2-4\)

\(=\left(x-y\right)^2-2^2\)

\(=\left(x-y-2\right)\left(x-y+2\right)\)

\(e,9-\left(x-y\right)^2\)

\(=3^2-\left(x-y\right)^2\)

\(=\left[3-\left(x-y\right)\right]\left[3+\left(x-y\right)\right]\)

\(=\left(3-x+y\right)\left(3+x-y\right)\)

\(=\left(-x+y+3\right)\left(x-y+3\right)\)

\(f,\left(x^2+4\right)^2-16x^2\)

\(=\left(x^2+4\right)^2-\left(4x\right)^2\)

\(=\left(x^2+4-4x\right)\left(x^2+4+4x\right)\)

\(=\left(x^2-2\cdot x\cdot2+2^2\right)\left(x^2+2\cdot x\cdot2+2^2\right)\)

\(=\left(x-2\right)^2\left(x+2\right)^2\)

#\(Toru\)

26 tháng 9 2023

c ơn bn nhiều ạ

 

24 tháng 4 2017