Answer
$2.752, \ or, \ -0.413$
Work Step by Step
For the equation $18.9x^2 -44.2x-21.5= 0$, we use the quadratic formula as follows
$$
x=\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a},
\\
a=18.9, \quad b=-44.2, \quad c=-21.5
.$$
That is, $$ x=\frac{44.2\pm \sqrt{44.2^2-4(18.9)(-21.5)}}{2(18.9) }=2.752, \ or, \ -0.413
.$$
