Question

If x-1/x = √5, find the value of x+1/x.
Plzz tell fast.​

Answer 1

Answer:

using identity

${(x + \frac{1}{x} )}^{2} - {(x - \frac{1}{x} )}^{2} = 4 \\ {(x + \frac{1}{x} )}^{2} - {( \sqrt{5} )}^{2} = 4 \\ {(x + \frac{1}{x} )}^{2} - 5 = 4 \\ {(x + \frac{1}{x} )}^{2} = 4 + 5 \\ {(x + \frac{1}{x} )}^{2} = 9 \\ x + \frac{1}{x} = 3$