Find the value of the expression when $x=9$x=9:
$6x+4$6x+4
Find the value of the expression when $x=3$x=3:
$3x^2-7x-4$3x2−7x−4
Find the value of the expression when $x=-3$x=−3:
$-3x^3+4x^2+7x+5$−3x3+4x2+7x+5
Find the value of the expression when $x=8$x=8:
$\frac{x+6}{x+5}$x+6x+5