Hello Caleb
You need to have polynomial fist so cancel x^2 on right
x^2 +3x - 10. =0 then you can factor this.
you need to find factors of -10 and sum of these factors should be 3;
-10 = 10*-1. (but when you add these get 9)
5* -2. (Yes, 5 +-2 =3, so you use these factors)
x^2 +3x - 10 = (x+5) (x-2) = 0
x+5 = 0 and x=-5,
x -2 =0 and x= 2
hope that helps