Question 251443
{{{(x^2-4x-21)/(x^2+2x-63)}}}
.
Factoring the numerator:
{{{x^2 -4x -21 = (x-7)(x+4)}}}
.
Factoring the denominator:
{{{x^2 +2x -63 = (x-7)(x+9)}}}
.
The '(x-7)' factors cancel.
.
{{{(x+4)/(x+9)}}}