Work: 5√2 + √18 First you must find the largest perfect square in √18: The perfect square happens to be 9 √18 => 9√2 You must then simplify 9 since it is a perfect square: 9√2 => 3√2 Then you must add both terms together: 5√2 + 3√2 = 8√2 Answer: 8√2 or 8 square root 2