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How do you solve $x^{2} - 1 = 80$ $x^2-1=80$ ?

1 Answer

Ratnaker Mehta · JMicheli

Jul 25, 2016

$x = \pm 9$ $x=+-9$

Explanation:

$x^{2} - 1 = 80$ $x^2-1=80$

$\Rightarrow x^{2} - 81 = 0$ $rArr x^2-81=0$

$\Rightarrow (x + 9) (x - 9) = 0$ $rArr (x+9)(x-9)=0$

$\Rightarrow x = \pm 9$ $rArr x=+-9$ is the solution.

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