Question

A) -5x^2 (2x^2+x-3)

B) 4-(x+3) (x-3)+(x+7)^2       C) (x-4) (x^2-2x+7)

 

Answer 1

b: Ta có: \(4-\left(x+3\right)\left(x-3\right)+\left(x+7\right)^2\)

\(=4-x^2+9+x^2+14x+49\)

=14x+62

Answer 2

a) \(-5x^2\left(2x^2+x-3\right)=-10x^4-5x^3+15x^2\)

b) \(4-\left(x+3\right)\left(x-3\right)+\left(x+7\right)^2=4-x^2+9+x^2+14x+49=14x+62\)

c) \(\left(x-4\right)\left(x^2-2x+7\right)=x^3-2x^2+7x-4x^2+8x-28=x^3-6x^2+15x-28\)