Question

Numbers 20 - 22 please

Answer 1

$(x+5)(x+2)=x^2+2x+5x+10=x^2+7x+10\\\\ (x-1)(2x^2-4x+10)=2x^3-4x^2+10x-2x^2+4x-10=\\ =2x^3-6x^2+14x-10\\\\ (c^2-10)(4c+3)=4x^3+3c^2-40c-30$