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#