Find the values of the following expressions for $x=2$.

$x+4$

Find the values of the following expressions for $x=2$.

$4x-3$

Find the values of the following expressions for $x=2$.

$19-5x^2$

Find the values of the following expressions for $x=2$.

$100-10x^3$

Find the value of the following expressions when $n=– 2$.

$5n-2$

Find the value of the following expressions when $n=– 2$.

$5n^2+5n-2$

Find the value of the following expressions when $n=– 2$.

$n^3+5n^2+5n-2$

Find the values $a+b, 7a-4b, a^2+2ab+b^2, a^3-b^3$ when $a=3$ and $b=2$.