SOLUTION: If x=3+√5 then the value of x-1/x will be 3-√5 2.25+1.25√2 6 None

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Question 1132451: If x=3+√5 then the value of x-1/x will be
3-√5
2.25+1.25√2
6
None
Found 2 solutions by greenestamps, Boreal:
Answer by greenestamps(13200) (Show Source):
You can put this solution on YOUR website!

Calculate 1/x by multiplying numerator and denominator by the conjugate:

Now perform the addition x+1/x, combining rational and irrational parts....

Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website!
If this is x-(1/x) then this is (x^2-1)/x
That is (9+6 sqrt(5)-1)/3+ sqrt(5) or (8+6 sqrt(5))/(3 + sqrt(5))
None would be the answer
BUT
if it is (x-1)/x
then it is (2+ sqrt(5)/(3+ sqrt(5)). Multiply top and bottom by the conjugate 3-sqrt(5) to get 6+sqrt(5)-5 divided by 4 or (1+sqrt(5))/4
None
Numerically, this is 5.236-(1/5.236) or 4.236/5.236, depending upon how it is grouped. The two possibilities give answers of 5.045 or 0.809.
3- sqrt(5) is 0.763