Question

explain how you would use the quadratic formula to solve x^2 + 7x = –3. Why is the quadratic formula the best method to use?

Answer 1

you're using an equation that is based on "ax^2 + bx + c = 0"
the first step is getting that form

Answer 2

from there, its just plug-and play

its not too hard to reason why, just try out the other methods like factoring and see what happens.