Work Step by Step
First, find two numbers that multiply together to get 98. In this case, the numbers that I used to get 98 were 49 and 2 because $49\times2$ is 98. Since the number 2 cannot be broken down anymore and it has no pair (another two), it stays under the radical. However, 49 is a perfect square and can break down into $7\times7$. Since 7 is a pair with itself, it goes outside of the radical and leaves the 2 inside giving the answer of $7\sqrt 2$.