Factoring+assignment

1.) Explain in your own words the rules you must use to factor. x^2+8x+15 you must find the factor's of end number and then they must add up to the number plus x

2.)Explain in your own words how to factor x^2-3x-18and how you decide which number gets the negative. you would find the factor's of 18 and then they must =the middle number so the factor for 18 would be 6 and 3 or 2 and 9 in this case it is 6 and 3 the six would be a negative because you can't get negative out of three it would have to be a -6 cuz if you add 3+-6 you get -3 and then you would do (x-6)(x+3) would be your answer

3.)Explain in your own words how to factor x-12x+36 and why the 26 is positive but why the 12 is negative. i don't know that one