5 / 4+√5

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

Question

5 / 4+√5

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

anonymous · Answer

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

anonymous · Answer

Multiply both nominator and denominator I mean.

anonymous · Answer

I have no clue

anonymous · Answer

$$\frac{5(4-\sqrt{5})}{(4+\sqrt{5})(4-\sqrt(5))}=\frac{20-5\sqrt{5}}{16-25}$$

Are you still with me?

anonymous · Answer

Yeah

anonymous · Answer

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.

anonymous · Answer

Yeah to me its really confusing but i appreciate the help

anonymous · Answer

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.