If f(x) = 5x - 12, find a value for x so that f(x) = f(2x + 1).
f(x) = f(2x + 1)
5x - 12 = 5(2x + 1) - 12
5x = 5(2x + 1)
x = 2x + 1
-x = 1
x = -1