Question

(8-√2)(9-√ 5)

Answer 1

\((a+b)(c+d)=ac+ad+bc+bd\)

\(\sqrt{a}\sqrt{b}=\sqrt{ab}\)

Try using these rules and show me what you get.

Answer 2

72+square root of 10?

Answer 3

You did \((a+b)(c+d)=ac+bd\) which is a common mistake. So common it has a name: Freshman's Dream

Using the first rule I showed you, we have

\((8-\sqrt{2})(9-\sqrt{5})=8*9-8\sqrt{5}-9\sqrt{2}+\sqrt{2}\sqrt{5}\)

Now use the other rule and simplify some.