Question

x+1/x=3. Then x2+1/x2 =?

Answer 1

$x + \frac{1}{x} = 3 \\ {(x + \frac{1}{x} )}^{2} = 9 \\ {x}^{2} + \frac{1}{ { x }^{2} } + 2 \times x \times \frac{1}{x} = 9 \\ {x}^{2} + \frac{1}{ {x}^{2} } = 7$
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Answer 2

(x+1/x)^2=(3)^2
x^2+1/x^2+2(x)(1/x)=9
x^2+1/x^2+2=9
=>x^2+1/x^2=9-2
=>x^2+1/x^2=7

Hope u understood...