Question

If x^2 +1 /X^2 = 51, find x-1 / x

Answer 1

(x - 1/x)^2 = x^2 - 2 + 1/x^2.

But x^2 + 1/x^2 = 51.

Thus, (x-1/x)^2 = 51 - 2 = 49.

Therefore, x-1/x = sqrt (49) = +/-7

x-1/x = +/-7.

Answer 2

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