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