Question

Помогите решить 1 и 2

Answer 1

№1
x^2-10x+21-6x^2+10x=21-5x^2
4a^2-8a-a^2+8a-16=3a^2-16
2m^2+4m+2-4m=2m^2+2=2(m^2+1)

№2
x^3-9x=x(x^2-9)=x(x-3)(x+3)
-5a^2-10ab-5b^2=-5(a^2+2ab+b^2)=-5(a+b)^2