Answer
$q=-\frac{7}{2}$ or $q=-\frac{1}{4}$
Work Step by Step
Set up the function: $-24q^2-90q-21=0$
with $a=-24, b=-90, c=-21$
Find $q$ by using:
$q=\frac{-b \pm \sqrt b^2-4ac}{2a}=\frac{-(-90)\pm\sqrt (-90)^2-4.(-24).(-21)}{2.(-24)}=\frac{90\pm78}{-48}$
$q=\frac{90+78}{-48}$ or $x=\frac{90-78}{-48}$
$q=-\frac{7}{2}$ or $q=-\frac{1}{4}$