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2 years ago

X^2+1/x^2=18 find x-1/x

Mathematics

1 answer:

MAVERICK [17]2 years ago

4 0

Notice that

$\left(x-\dfrac1x\right)^2=x^2-2+\dfrac1{x^2}=18-2=16$

which tells us

$x-\dfrac1x=\pm4$

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