Chapter 9 - Quadratic Functions and Equations - 9-6 The Quadratic Formula and the Discriminant - Practice and Problem-Solving Exercises - Page 571: 15

$x=12, -2.6$

$5x^2-47x = 156$ $5x^2-47x-156=156-156$ $5x^2-47x-156 = 0$ $x= (-b±\sqrt {b^2-4ac})/2a$ $x= (-(-47)±\sqrt {(-47)^2-4*5*-156})/2*5$ $x= (47)±\sqrt {2209+3120})/10$ $x= (47±\sqrt {5329})/10$ $x= (47±73)/10$ $x=(47+73)/10$ $x=120/10 =12$ $x=(47-73)/10$ $x = -26/10 = -2.6$