Suppose you want to solve it:
(2x + 1)^2 = 36
2x + 1 = sqrt(36) or = -sqrt(36)
2x + 1 = 6 or = -6
2x = 6 - 1 or 2x = -6 - 1
2x = 5 or 2x = -7
x = 5/2 or x = -7/2
Suppose you want to expand it:
(2x + 1)^2 = 36
4x^2 + 4x + 1 = 36
4x^2 + 4x + 1 - 36 = 0
4x^2 + 4x - 35 = 0