Question

5 / 4+√5

1) 20-√5 / 11
2) 20-5√5 / 11
3) 5√5 / 4√5+5
4) 5√5 / 9

Answer 1

multiply 5 / (4+√5) by (4-√5) to get started

Answer 2

Multiply both nominator and denominator I mean.

Answer 3

I have no clue

Answer 4

\[\frac{5(4-\sqrt{5})}{(4+\sqrt{5})(4-\sqrt(5))}=\frac{20-5\sqrt{5}}{16-25}\]

Are you still with me?

Answer 5

Yeah

Answer 6

Well at this point you can pretty easily see that 1,2 and 4 are not correct. so 3 is the answer. It's still not very pretty though.

Answer 7

Yeah to me its really confusing but i appreciate the help

Answer 8

Yeah, well, I was going for this representation:
\[-\frac{20}{9}+\frac{5\sqrt{5}}{9}\]
But that wasn't an option. This way you don't have roots in your denominator.