Simplify evaluation 3 (a + 1) ^ 2 - (2a + 1) (2a-1), where a = 1

Simplify evaluation 3 (a + 1) ^ 2 - (2a + 1) (2a-1), where a = 1

Original formula = 3 (a ^ 2 + 2A + 1) + (4a ^ 2-1)
=3a^2+6a+3-4a^2+1
=-a^2+6a+4
=-1+6+4
=9