Two things you need to know. a square root that is squared becomes the number under the root sign the general formula is a^2 + 2ab + b^2 sqrt(5)^2 + 2*sqrt(5)*sqrt(3) + sqrt(3)^2 5 + 2sqrt(15) + 3 8 + 2sqrt(15) <<<<===== Stop! Don't go any further. That is your answer.
