Question

1) (a-x)^2+(a+x)^2=
2) 2(x+6)^2-(20x+70)=

Answer 1

$(a-x)^2+(a+x)^2=a^2+x^2-2ax+a^2+x^2+2ax=2a^2+2x^2$
$2(x+6)^2-(20x+70)=2x^2+72+24x-20x-70=2x^2+2+4x= \ =2(x^2+2x+1)$