Easy thật : 

\(a^3+b^3-\left(a^2-2ab+b^2\right)\left(a-b\right)\)

\(=a^3+b^3-\left(a-b\right)^2\left(a-b\right)\)

\(=a^3+b^3-\left(a-b\right)^3\)

Thay \(a=-4;b=4\)vào biểu thức , ta được : 

\(\left(-4\right)^3+4^3-\left(-4-4\right)^3\)

\(=8^3\)

\(=512\)

a³ + b³ - ( a² - 2ab + b² )( a - b )

= a³ + b³ - ( a - b )²( a - b )

= a³ + b³ - ( a - b )³

Thế a = -4 ; b = 4 ta được

(-4)³ + 4³ - ( -4 - 4 )³

= -64 + 64 - ( -512 )

= 512

\(B=\sqrt{x^2+8x+14}+\sqrt{9-x^2}\)

ĐKXĐ :

\(\hept{\begin{cases}x^2+8x+14\ge0\\9-x^2\ge0\end{cases}}\)\(\Leftrightarrow\hept{\begin{cases}x\ge-4-\sqrt{2}\\x\le3\end{cases}}\)

\(\Leftrightarrow-4-\sqrt{2}\le x\le3\)

A )  \(3\left(x-1\right)^2-3x\left(x-5\right)=1\)

\(\Leftrightarrow3\left(x^2-2x+1\right)-3x^2+15x=1\)

\(\Leftrightarrow3x^2-6x+3-3x^2+15x=1\)

\(\Leftrightarrow7x+3=1\)

\(\Leftrightarrow7x=-2\)

\(\Leftrightarrow x=\frac{-2}{7}\)

B)  \(\left(6x-2\right)^2+\left(5x-2\right)^2-4\left(3x-1\right)\left(5x-2\right)=0\)

\(\Leftrightarrow\left(6x-2\right)^2+\left(5x-2\right)^2-2.2\left(3x-1\right)\left(5x-2\right)=0\)

\(\Leftrightarrow\left(6x-2\right)^2+\left(5x-2\right)^2-2\left(6x-2\right)\left(5x-2\right)=0\)

\(\Leftrightarrow\left[\left(6x-2\right)-\left(5x-2\right)\right]^2=0\)

\(\Leftrightarrow\left(6x-2\right)\left(5x-2\right)=0\)

\(\Leftrightarrow6x-2-5x+2=0\)

\(\Leftrightarrow x=0\)

câu a sai rồi bạn ơi câu b thì đúng

bằng 11 nhé 

3 + 3 + 5 = 11

^_^

a)  \(3x^2-6x=3x\left(x-2\right).\)

b)   Không thể phân tích thành nhân tử

c)   \(4x^2\left(2x-y\right)-12x\left(2x-y\right)=\left(2x-y\right).\left(4x^2-12\right)=4\left(2x-y\right).\left(x^2-3\right)\)

d)   \(7\left(x-3y\right)-2x\left(3y-x\right)=7\left(x-3y\right)+2x\left(x-3y\right)=\left(x-3y\right).\left(2x+7\right)\)

f)   \(6\left(x-2y\right)-3\left(2y-x\right)=6\left(x-2y\right)+3\left(x-2y\right)=9\left(x-2y\right)\)

a,15(3x-2y) chia het cho 17

15(3x-2y)-17(2x-y) chia het cho 17

45x-30y-34x+17y chia het cho 17

11x-13y chia het cho 17

b,5(4x+3y) chia het cho 13

5(4x+3y)-13(x+y) chia het cho 13

20x+15y-13x-13y chia het cho 13

7x+2y chia het cho 13

c,x+99y chia het cho 7

x+99y-98y chia het cho 7

x+y chia het cho 7

x² -3² = 6x -x² -18 +3x 

(x -3 )(x+3 ) =9x -x² - 9

 x² +3x-3x- 9 =9x - x² -9

x² - x ² -9x = -9 +9 

-9 x = 0

=> x = 0