It is.

Let a = 1.
a^2 = a (multiply both sides by a)
a^2 - 1 = a - 1 (subtract 1 from both sides)
(a + 1)(a - 1) = (a - 1) (factor it)
(a + 1) = 1 (cancel common factors)
1 + 1 = 1 (substitution.)

QED/ :)




Reply via email to