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

1 Answer
Mar 14, 2017

Answer:

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

Explanation:

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.