To simplify you must first multiply the two terms together using the FOIL method.
The FOIL method is used to multiply two terms together by multiplying the First terms together, then the outer terms together, the inner terms together, and the last terms together.
Here the math:
(x-7)(x+9)------------------------------------FOIL
(x*x)+(x*9)+(-7*x)+(-7*9)-----------------Multiply
[tex] x^{2} +9x-7x-63[/tex]---------------------Combine like terms
[tex] x^{2} +2x-63[/tex]-----------------------------Simplify
So, the answer is [tex] x^{2} +2x-63[/tex]
