Question 538112
x^2 -8x -9 = 0
.
So, to factor it you need to find two powers of 9 that have a difference of 1.
-8 = -9+1
.
(x-9)(x+1) = x^2 -8x -9
.
That means x = 9 or -1.
.
{{{
graph(500,500,-10,10,-25,25,x^2-8*x-9)
}}}
.
Done.