Subtract $4a-7ab+3b+12$ from $12a-9ab+5b-3$

Subtract $4p^{2}q-3pq+5p{q}^2-8p+7q-10$ from $18-3p-11q+5pq-2p{q}^2+5p^{2}q$

Simplify $3x(4x- 5)+3$and find its values for

$x=3$

Simplify $3x(4x-5)+3$ and find its values for

$x=\frac{1}{2}$

Simplify $a(a^2+a+1)+5$ and find its value for 

$a=0$

Simplify $a(a^2+a+1)+5$ and find its value for

$a=-1$

Simplify:

$(\mathrm{a}+\mathrm{b})(\mathrm{c}-\mathrm{d})+\left(\mathrm{a}-\mathrm{b}\right)(\mathrm{c}+\mathrm{d})+2(\mathrm{ac}+\mathrm{bd})$

Simplify:

$(\mathrm{x}+\mathrm{y})(2\mathrm{x}+\mathrm{y})+(\mathrm{x}+2\mathrm{y})(\mathrm{x}-\mathrm{y})$