Chapter 9 - Quadratic Functions and Equations - 9-5 Completing the Square - Lesson Check - Page 579: 3

$m=14$ or $m=-21$

$m^2+7m-294=0$ $m^2+2.m.\frac{7}{2}+\frac{49}{4} =294+\frac{49}{4}$ $(m+\frac{7}{2})^2=\frac{1225}{4}$ $(m+\frac{7}{2})^2=(\frac{35}{2})^2$ $m+\frac{7}{2}=\pm \frac{35}{2}$ $m+\frac{7}{2}=\frac{35}{2}$ or $m+\frac{7}{2}=-\frac{35}{2}$ $m=14$ or $m=-21$