Answer:
ab = 2
Step-by-step explanation:
You know that ...
(a +b)^2 = a^2 +2ab +b^2
Rearranging, we can solve for ab ...
2ab = (a^2 +b^2) -(a +b)^2
ab = ((a +b)^2 -(a^2 +b^2))/2 = (3^2 -5)/2
