giúp mình với , ( bài 30 Câu 1,2)

Bài 30

1)(x+5)³-15x(x+10)

=x³+15x²+75x+125-15x²-150x

=x³-75x+125

2)(x-2)³-(x-5)²

=x³-6x²+12x-8-x²+10x-25=x³-7x²+22x-33

3)(x+2)(x²-2x+4)-(x³+8)

=(x³+8)-(x³+8)=0

4)(x-3)(x²+3x+9)-(x²-1)(x+27)

=x³-27-x³+x-27x²+27=x-27x²

5)(3-x)³-(x+3)(x²-3x+9)

=27-27x+9x²-x³-x³-27=-27x+9x²

6)(x-2)(x²+2x+4)-x(x-3)(x+3)

=x³-8-x²+9x

Bài 31

1)(x+3)(x-4)+(x-4)²

=x²-x-12+x²-8x+16=2x²-9x+4=(x-4)(2x-1)

2)(x-2)³-(3+x²)(3-x)

=x³-6x²+12x-8-9-3x²+3x+x³

=2x³-9x²+15x-16

3)x(x-14)-10(x-1)²

=x²-14x-10x²+20x-10

=-9x²+6x-10

4)2x(x+2)-(x+2)(x-2)

=(x+2)(2x-x+2)=(x+2)²