Solve quadratics by inspection, square roots, completing the square, formula, and factoring; express complex solutions.
Find a missing coefficient in a quadratic equation when one solution is given
Problem
Find the missing coefficient in \(x^2+kx+12=0\) given that \(x=3\) is a solution.
Big Picture
What this problem is really about
A known solution must make the original equation true. We’ll substitute the given x-value everywhere it appears, simplify to a linear equation in the missing coefficient, solve that equation, and plug the coefficient back in to verify the root.
Inside Gozunta
Turn the preview into practice.
More than a preview
Gozunta lets you study this problem—and more than 10,000 others.
Create targeted learning sessions, use hints, check your answer, read the walkthrough, watch the video, print the work, and track your progress.
