Question

Giúp mình nha mọi người ơi

Answer 1

1: Ta có: \(-\left(x+3\right)\left(x+2\right)+\left(2x-3\right)\left(5-x\right)\)

\(=-x^2-5x-6+10x-2x^2-15+3x\)

\(=-3x^2+8x-21\)

3: Ta có: \(\left(-x+6\right)\left(-x-2\right)+\left(3x-1\right)\left(-2x-3\right)\)

\(=\left(x-6\right)\left(x+2\right)-\left(3x-1\right)\left(2x+3\right)\)

\(=x^2-4x-12-6x^2-9x+2x+3\)

\(=-5x^2-11x-9\)