Find the missing side lengths. Leave your answers as radicals in simplest form. A) x = 5√3, y = 3
B) x = 5√3 , y = 2
5
C) x = 10, y = 2
5
D) x = 10, y = 5

To find out what the perfect square trinomial is, look at the middle term and the last term.

(Middle term ÷ 2)² has to be the last term

y² + 6y + 36
divide 6 ÷ 2 = 3
square it 3² = 9
This trinomial is not a perfect square trinomial.

Your answers are 

y² + 20y + 100 , y² + 18y + 81