Algebrahard · Past Paper
If x^2 + 1/x^2 = 7, find x + 1/x (for positive x).
A3
B9
Csqrt(7)
D5
✓ Correct Answer: A — 3
(x + 1/x)^2 = x^2 + 1/x^2 + 2 = 7 + 2 = 9. So x + 1/x = 3.
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✓ Correct Answer: A — 3
(x + 1/x)^2 = x^2 + 1/x^2 + 2 = 7 + 2 = 9. So x + 1/x = 3.
Share this question