I’d use the app Socratic, the apps always factors the quadratic formula and it gives you the steps on how it done.
1. X^2+7x+12=0
Identify a,b, and c. Which x^2 is a, 7 is b and c is 12.
Find two numbers that multiply together to equal c which is 12 which is 3•4
And add two numbers that equal to b which is 7 which is 3+4
= (x+3)(x+4)=0
Set each factor to zero
X+3=0
= -3
X+4=0
=-4