If r =9, b=5, and g = -6, what does (r + b - g)(b + g) equal?

Remember
-(-x)=+x since negatives cancel
and
+(-x)=-x

try to simplify parenthaseess first

r=9
b=5
g=-6
(r+b-g)(b+g)
(9+5-(-6))(5+-6)
(9+5+6)(5-6)
(14+6)(-1)
(20)(-1)
-20