How do you solve #x^2-x-72=0#?

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Answer 1 · 2017-03-14T12:02:50

#x=9" "or x=-8# are the two solutions.

To solve a quadratic equation (one with an #x^2# term), there are three options:

In this case the quadratic trinomial can be factored.

#x^2 -x-72 =0" "# find factors of 72 which differ by 1.

#(x-9)(x+8)=0#

Either of the factors could be equal to #0#.

If #x-9=0" "hArr" " x =9#

If #x+8=0" "hArr" "x =-8#

#x=9" "or x=-8# are the two solutions.