Question

Bài 1: tính và rút gọn

a) (x-2)² -x²

b) (4x-5)(3x+2)

Answer 1

a) \(\left(x-2\right)^2-x^2\)

\(=\left(x-2-x\right)\left(x-2+x\right)\)

\(=-2\left(2x-2\right)\)

\(=-4x+4\)

b) \(\left(4x-5\right)\left(3x+2\right)\)

\(=12x^2+8x-15x-10\)

\(=12x^2-7x-10\)

Answer 2

a) (x-2)²-x²

=(x-2-x).(x-2+x)

=2.(2x-2)

=2.2(x-1)

=4.(x-1)

b) (4x-5)(3x+2)

=12x²+8x-15x-10

=12x²-7x-10

Chúc bn học tốt !!!!!!!!!!!!!!!!!!!!!!