SOLUTION: Use the factoring to solve the quadratic equation. Check by substitution or by using a graphing utility. 5x^2 =8x+21

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Use the factoring to solve the quadratic equation. Check by substitution or by using a graphing utility. 5x^2 =8x+21      Log On


   

Question 870278: Use the factoring to solve the quadratic equation. Check by substitution or by using a graphing utility.
5x^2 =8x+21
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
5x^2 =8x+21
5x^2 -8x-21=0
5x^2-15x+7x-21=0
5x(x-3)+7(x-3)=0
(x-3)(5x+7)=0
x=3 OR x=-7/5
5*3^2=45
8*3+21=45