# Math Help - surds

1. ## surds

ok i know this is simple but i cant see how to do it

it needs to be in the for a√b (thats supposed to be a square root)

7√2 - 3√8

thanks

2. Hello,
Originally Posted by pop_91
ok i know this is simple but i cant see how to do it

it needs to be in the for a√b (thats supposed to be a square root)

7√2 - 3√8

thanks
Note that $8=4 \times 2$

$\implies \sqrt{8}=\sqrt{4} \times \sqrt{2}=2 \sqrt{2}$

Can you finish it ?