Question

Bài 1: Rút gọn các biểu thức sau:

1, (x-2)³+6.(x+1)²-x³

2, 2x.(2x-1)²-3x.(x+3).(x-3)-4x.(x+1)²

3, (x-2)³-x.(x+1).(x-1)+6x.(x-3)

4, (x-3).(x²+3x+9)+x.(x+2).(2-x)

Answer 1

HELP ME!!! các bạn ơi giúp mình với

Answer 2

các bạn ơi giúp mình với đi!!!

Answer 3

1,

(x-2)³+6.(x+1)²-x³

=(x-2)³-x³+6.(x²+2x+1)

\(=\left(x-2-x\right)\left[\left(x-2\right)^2+\left(x-2\right)x+x^2\right]+6\left(x^2+2x+1\right)\)

=(-2)(x²-4x+4 +x²-2x+x²)+ 6(x²+2x+1)

=(-2)(3x²-2x+4)+6(x²+2x+1)=-6x²+4x-8+6x²+12x+6

=16x-2

Answer 4

2, 2x(2x-1)²-3x(x+3).(x-3)-4x(x+1)²

=2x(4x²-4x+1)-3x.(x²-3²)-4x(x²+2x+1)

=8x³-8x²+2x-3x³+27x-4x³-8x²-4x

=x³-16x²+25x

Answer 5

3,(x-2)³-x(x+1)+6x(x-3)

=x³-3.x²2+3.x.2²-2³ -x²-x+6x² -18x

=x³ -6x²+12x-8- x²-x+6x²-18x

=x³ -8- x²-x-18x+12x=x³-8-7x-x²