equation: simplify -1(-a)^2 + (-(-a))^2

Answer 1

Just work your way out from the inside

-1(-a)^2 + (-(-a))^2
= -1(-a)^2 + (a)^2
= -1*a^2 + a^2
= -a^2+a^2
= 0

recall that (-a)^2 = (-a)(-a) = +a^2