Find the value of $a^2+a{b}^2+a^{2}b+b^2$ at $a=-1$ and $b=2$.

The value of $\left(\frac{-7}{5}{x}^{2}y\right)\times \left(\frac{3}{2}x{y}^2\right)\times \left(\frac{-6}{5}{x}^3{y}^3\right)$ at $x=2, y=1$, is $\frac{63}{25}k$, then find $k$.

Find the cost of $3$ notebooks and $1$ magazine in terms of $y$, if the cost of $1$ notebook is $₹2y$ and that of $1$ magazine is $₹\left(y+3\right)$.

Find the value of $\frac{3c^3}{8}-21$, when $c=-2$.

Find the value of expression $\left(x-6\right)-\left(x-5\right)+40-17\left(x-2\right)$ at $x=\frac{1}{17}$.

Simplify the given expression and find its value at $x=-44 : 2\left(x-4\right)-\left(x+4\right)+54+\left(x-5\right)-\left(x-10\right)$

The perimeter of a triangle is $5-3a+7a^2$ and two of its sides are $2a^2+3a-2$ and $3a^2-a+3.$ Find the third side of the triangle.

By how much is $-12x+2y$ greater than the sum of $-18x+6y$ and $5x-25y$?