How do you solve $x^2 + 7 = 71$ ?

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Answer 1 · 2016-08-27T06:46:22

$x = -8 or x=+8$

As this is a quadratic, we would usually make it =0,
But this is a special case where there is no term in x.

#x^2 =71-7

$x^2 = 64$

$x= +-sqrt64$

$x = +-8$

We could also have factored as the difference of two squares.

$x^2 -64 = 0$

$(x+8)(x-8)= 0$

$x = -8 or x=+8$

How do you solve x^2 + 7 = 71x^2 + 7 = 71?