## anonymous 5 years ago equation that I need help with is 8 over 3 plus sqrt 7

1. anonymous

$\frac{8}{3+\sqrt{7}}$

2. anonymous

is that it

3. anonymous

well if it is multiply top and bottom by conjugate $\frac{8}{3+\sqrt{7}}*\frac{3-\sqrt{7}}{3-\sqrt{7}}$ $=\frac{24-8\sqrt{7}}{2}$ factor out a 2 on top which cancels the 2 on bottom leaving $= 12-4\sqrt{7}$

4. anonymous

wonderful! how did you come up with the 8, though? is it that you must include the same number you multiply with in the top equation?

5. anonymous

and how in the heck did you get 2?

6. anonymous

oh, never mind. thank you!

7. anonymous

by distributing on top, FOIL on bottom your welcome :)

8. anonymous

quick question- for these types of problems, will the denominator always be 2?