How do you simplify radical square roots

Break the number within the radical symbol into 2 numbers: another number and a perfect square (when multiplied, they get the original number).

An example would be 48. The square root of 48 can be evaluated by breaking apart 48 into 16 (a perfect square) and 3 (another number). The square root of 16 is 4, so you take this number out of the radical symbol. Leave 3 within the symbol as it cannot be further reduced.

√48 = 4 √3.

The correct answer is -20y