Nhưngz câu mik tích thì làm hộ mik ạ

Đáp án:

Bài 4

 c) x.(2x-3)+2x².(x-2)-2x.(x²-x+1)+5.(x-1)

 = 2x²-3x+2x³-4x²-2x³+2x²-2x+5x-5

 = (2x³-2x³)+(2x²-4x²+2x²)-(3x+2x-5x)-5

 =          -5

d) 2x.(6x-4)-5x².(8+3x)+2.(5x²+4x+1)+3x².(5x+6)

 = 12x²-8x-40x²-15x³+10x²+8x+2+15x³+18x²

 = (-15x³+15x³)+(12x²-40x²+10x²+18x²)-(8x-8x)+2

 =        2

Bài 5

c) A= 4.(x-1).(x+1)

    A= (4x-4).(x+1)

    A= 4x²+4x-4x-4

    A=   4x²-4

d) A= (x+3).(x²+3x-5)

    A= x³+3x²-5x+3x²+9x-15

    A= x³+(3x²+3x²)-(5x-9x)

    A=  x³+6x²+4x

e) A=(xy-1).(xy+5)

    A= x²y²+5xy-xy-5

    A= x²y²+(5xy-xy)-5

    A=  x²y²+4xy-5

f) A= (x²-2x+3).(x-5)

   A= x³-5x²-2x²+10x+3x-15

   A= x³-(5x²+2x²)+(10x+3x)-15

   A=    x³-7x²+13x-15