Expand and simplify the following
a) (x+3)^2
b) (3x-6)^2
c) (x-4)^2
a) (x+3)^2 = (x+3)(x+3) = x(x+3) + 3(x+3) = x^2 + 3x + 3x + 9 = x^2 + 6x + 9
b) (3x-6)^2 = (3x-6)(3x-6) = 3x(3x-6) - 6(3x-6) = 9x^2 - 18x - 18x + 36 = 9x^2 - 36x + 36
c) (x-4)^2 = (x-4)(x-4) = x(x-4) - 4(x-4) = x^2 - 4x - 4x + 16 = x^2 - 8x + 16