This is a solution to the equation, but not the complete solution. To solve a quadratic equation, factor it, set each factor equal to 0, and solve each equation. You may have thought that $\displaystyle{\left({x}+{2}\right)}\usepackage{cmbright}\Huge\$ could not be equal to 0, because you were thinking of the addition of two positive numbers. However, x could be positive or negative.