Answer
$2.38, \ or, \ -2.38$
Work Step by Step
For the equation $3x^2 -17= 0$, we use the quadratic formula as follows
$$
x=\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a},
\\
a=3, \quad b=0, \quad c=-17
.$$
That is, $$ x=\frac{0\pm \sqrt{0-4(3)(-17)}}{2(3) }=2.38, \ or, \ -2.38
.$$
