The Quadratic Formula uses the a b and c from ax 2 bx c where a b and c are just numbers. Also the Formula is stated in terms of the numerical coefficients of the terms of the quadratic expression. To use the quadratic formula the equation must be equal to zero so move the 5 back to the left hand side.
Make sure that a 1 if a 1 multiply through the equation by before proceeding.
MIT grad shows how to solve any quadratic equation by factoring. Plus or minus the square root of b squared of 2 squared minus 4 times a times negative 7 times c which is 9. Combine all of the like terms and move them to one side of the equation. Simplify each equation then use the method of your choice to solve the system of equations for a b and c.