evaluate 2x to the 2nd power minus 1 when x is 3

Answer 1

could be:
(2x)^2 - 1 or 2x^2 -1, can't tell from your typing

I will assume the 2nd, if not, you do my first interpretation

2x^2 -1
= 2(3^2) - 1
= 2(9) - 1
= 17