1) (x-3)^2-2(x-3)(x+3)+(x+3 )^2 = x^2- 6x+9-2(x^2-3^2)+x^2+6x+9= x^2+9-2x^2+18+x^2+9=36
2)(2+x)^3+(x-1)^2-10x=x^3+6x^2+12x+8+x^2-2x+1-10x=x^3+7x^2+9
3)(a-2b)(2a^2-3ab-2b^2)=2a^3-3a^2b-2ab^2-4a^2b+6ab^2+4b^3=2a^3-7a^2b-2ab^2+6ab^2+4b^3=2a^3-7a^2b+4ab^2+4b^3