Evaluate Using the Given Value 2x^2-1 when x=3

$2 x^{2} - 1$ when $x = 3$

Replace the variable $x$ with $3$ in the expression.

$2 {(3)}^{2} - 1$

Simplify each term.

Raise $3$ to the power of $2$ .

$2 \cdot 9 - 1$

Multiply $2$ by $9$ .

$18 - 1$

Subtract $1$ from $18$ .

$17$