Find the perimeter of the following triangle.

Find the perimeter of the following rectangle.

Subtract the second term from first term.

$8x, 5x$

Subtract the second term from first term.

$5p, 11p$

Subtraction of the second term from first term $13m^2, 2m^2$ is $k m^2$. Find the value of $k$.

Find the value of the monomial $-x$, if $x=1$.

Find the value of the monomial $4x$, if $x=1$.

Find the value of the monomial $-2x^2$, if $x=1$.

Simplify and find the value of $4x+x-2x^2+x-1$ when $x=-1$.