Question

(3+5sqrt2)(4-sqrt2)

Answer 1

Have you tried FOIL?

Answer 2

It's very hard to help you if you won't answer me.

Answer 3

Yes

Answer 4

So what did you get?

Answer 5

12-3sqrt2+20sqrt4+5sqrt2

Answer 6

The Inside is 20sqrt2 isn't it?

Answer 7

\[(3+5\sqrt{2})(4-\sqrt{2})=12-3\sqrt{2}+20\sqrt{2}-5\sqrt{2}\sqrt{2})\]

Answer 8

\[5\sqrt{2}\sqrt{2}=5(2)=10\]

Answer 9

Also
\[-3\sqrt{2}+20\sqrt{2}=17\sqrt{2}\]

Answer 10

So we have
\[12+17\sqrt{2}+10=22+17\sqrt{2}\]

Answer 11

Do you understand?

Answer 12

Whoops. It's -10 so the result would be 2+17sqrt2

Answer 13

Okay, yes I do thank you