Find the value of the quadratic expression $3x^2$3x2 for each of the following $x$x-values.

$x=5$x=5

$x=-5$x=−5

Find the value of the following quadratic expression when $x=1$x=1.

$3x^2+1$3x2+1

Find the value of the following quadratic expression when $x=7$x=7.

Find the value of the following quadratic expression when $x=8$x=8.