## Precalculus (6th Edition)

$x^{2}+4x+4=0$ The discriminant is given by $b^{2}-4ac$. For this equation, $a=1$, $b=4$ and $c=4$ Let the discriminant be $D$. Substitute the known values into the formula and evaluate: $D=4^{2}-4(1)(4)=16-16=0$ Since the discriminant is equal to $0$, the equation has only one solution and it is a rational number.