x² + 13x - 30 = 0
first, to factor this, we need to find 2 numbers, that when added, equal 13. These same numbers must also multiply to equal -30
15 and -2 fit this criteria.
15 + -2 = 13
15 x -2 = -30
now we can put these numbers in place of 13 in our equation
x²-2x+15x-30=0
now we take the common value of the fist 2 numbers and place it on the outside. we do the same with the last 2 numbers.
x(x-2) +15(x-2) = 0
notice how the numbers in parentheses are the same. we can now take the outside numbers and have them with the numbers in parentheses.
(x+15)(x-2) = 0
this is the factored form.
if you needed to find x, you take the numbers that would make one of the parentheses equal 0
so x = -15, 2
hope this helps