Question

Find the exact value of the radical expression in simplest form.
the square root of 169 − the square root of 50 − the square root of 8

Answer 1

I know the answer and how to get it by getting the square roots of all of them like 13 - 5 square root of two - 2 square root of 2 witch gives you 13 - 7 square root of two i don't understand however why it is 5 square root of two and 2 square root of 2