Given the Quadratic Equation:
[tex]x^2-9x-36=0[/tex]You need to remember that the Zero Product Property states that if:
[tex]ab=0[/tex]Then:
[tex]a=0\text{ }or\text{ }b=0[/tex]In this case, you can factor the given equation by finding two numbers whose sum is -9 and whose product is -36. These numbers are 3 and -12. Then:
[tex](x+3)(x-12)=0[/tex]Based on the Zero Product Property, you know that:
[tex](x+3)=0\text{ }or\text{ }(x-12)=0[/tex]Then, by solving each part by "x", you get:
[tex]x=-3\text{ }or\text{ }x=12[/tex]Hence, the answer is:
[tex]x=-3\text{ }or\text{ }x=12[/tex]