Vieta theorem

For the mentioned quadratic equation (i.e that, which coefficient (in case x² is in it) is equal to figure one) x² + px + q = 0 root sum is equal to coefficient p which is drawn with the opposite sign and root’s product is equal to free term q:
x₁ + x₂ = -p
x₁x₂ = q

In case of unreduced quadratic equation ax² + bx + c = 0:
x₁ + x₂ = -b / a
x₁x₂ = c / a

In order not to make calculations manually just put values of coefficients into the set out below form.

You can use Vieta theorem for roots finding of quadratic equation.