Question

solve by factoring: x^2-6X-72=0

Answer 1

Notice that 72 is 12*6, and 6-12=-6

Answer 2

x^(2)-6x-72

For a polynomial of the form x^(2)+bx+c, find two factors of c (-72) that add up to b (-6). In this problem 6*-12=-72 and 6-12=-6, so insert 6 as the right hand term of one factor and -12 as the right-hand term of the other factor.
(x+6)(x-12)