You can put this solution on YOUR website! Another way of reading this problem is: if x=-3, what does 2x-5 equal? All they are asking is for you to do is plug in -3 in for x:
g(x) = 2x - 5
g(-3) = 2(-3) - 5
g(-3) = -6 - 5
g(-3) = -11
So your answer is g(-3) = -11.