evaluate (a+b)^2 and mutliply (g_6h(g-6h) thanks.

Answer 1

(a+b)^2 = a^2 + 2ab + b^2
(g-6h)^2 = g^2 -12 gh + 36h^2

I assumed that your (g_6h is supposed to be (g-6h). If you meant
g - 6h(g-6h), that would be something else again.