ax^2+bx+c=0
Solution:
- \frac{b}{2 a} - \frac{\sqrt{- 4 a c + b^{2}}}{2 a}, - \frac{b}{2 a} + \frac{\sqrt{- 4 a c + b^{2}}}{2 a}
x= -4 and x =-3
(x)^2 + 7x +12= (x)^2 + 4x +3x +12
= x(x+4)+3(x+4)
=(x+3)(x+4)=0
x=-3 , x=-4