Trả lời:

7x² - 7y² - 14x + 14y 

= 7 ( x² - y² - 2x + 2y )

= 7 [ ( x² - y² ) - ( 2x - 2y ) ] 

= 7 [ ( x - y )( x + y ) - 2 ( x - y ) ]

= 7 ( x - y )( x + y - 2 )

Answer:

\(x^3-2x^2+x-xy^2\)

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

\(=x[\left(x^2-2x+1\right)-y^2]\)

\(=x[\left(x-1\right)^2-y^2]\)

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

a,\(3x^2-30x+75=3\left(x^2-10x+25\right)=3\left(x-5\right)^2\)

b, \(xy-x^2-x+y=x\left(y-x\right)+\left(y-x\right)=\left(y-x\right)\left(x+1\right)\)

c,\(x^2-7x-8=x^2-8x+x-8=x\left(x-8\right)+\left(x-8\right)=\left(x-8\right)\left(x+1\right)\)

a) 3x² - 30x + 75 = 3.(x² - 10x + 25) = 3.(x² - 2.5.x + 5²) = 3.(x-5)²

b) xy - x² - x + y = x.(y-x) + (y-x) = (y-x).(x+1)

c) x² - 7x - 8 = x² + x - 8x - 8 = x.(x+1) - 8.(x+1) = (x+1).(x-8)

b) x² + 9x + 20 = x² + 4x + 5x +20 =x(x + 4) + 5(x + 4) = (x + 4)(x+ 5)

a) 7x^2-7y^2-14x+14y= 7 ( x^2 - y^2 ) - 14 ( x+y) = 14 ( 2(x^2) - 2 (x^2))- 28 ( 2x+2y)

= 28 ( 4 ( x^2)-4(y^2))- 28 ( 2x+2y)

= 28 (4(x^2-y^2) - 4(x+y)

= 28 (4( x^2-y^2-x+y ))

= 112 . ( x-y-x+y)

B= 2x^2+2x+3x+3
= 2x(x+1)+3(x+1)
=(x+1)( 2x+3)

C=3x^2-6x-x+2
=3x(x-2)-(x-2)
=(x-2)(3x-1)

2x⁴-7x³-2x²+13x+6=2x⁴-2x³-5x³+5x²-7x²+7x+6x+6=2x³(x-1)-5x²(x-1)-7x(x-1)+6(x+1)=(x-1)(2x³-5x²-7x)+6(x+1)=(x-1)(2x³+2x²-7x²-7x)+6(x+1)                       =(x-1)(2x²(x+1)-7x(x+1))+6x(x+1)=(x-1)(x+1)(2x²-7x)+6(x+1)                                 =(x+1)(2x³-7x²-2x²+7x+6)=(x+1)(2x³-9x²+7x+6)=(x+1)(2x³-6x²-3x²+9x-2x+6)       =(x+1)(2x²(x-3)-3x(x-3)-2(x-3))=(x+1)(x-3)(2x²-3x-2)=(x+1)(x-3)(2x²-4x+x-2)          =(x+1)(x-3)(2x(x-2)+(x-2))                                                                                  =(x+1)(x-3)(x-2)(2x+1)

do hk biết ghi dấu ngoặc vuông nên bài làm hơi rối nhan,nhưng trình bày zô là thấy đơn giản àk,đúng thì chọn đúng nhan

Uhm, thanks bạn, bạn siêu quá =)