Answer
$\frac{2}{3}\approx0.667, \ or, \ \frac{5}{3}\approx1.667$
Work Step by Step
For the equation $9x^2 -21x+10= 0$, we use the quadratic formula as follows
$$
x=\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a},
\\
a=9, \quad b=-21, \quad c=10
.$$
That is, $$ x=\frac{21\pm \sqrt{21^2-360}}{2(9) }=\frac{2}{3}\approx0.667, \ or, \ \frac{5}{3}\approx1.667$$
