Factorise of the expression $a{m}^2+b{m}^2+b{n}^2+a{n}^2$.

Factorise the expression $\left(lm+l\right)+m+1$

Factorise of the expression $y\left(y+z\right)+9\left(y+z\right)$.

Factorise the expression $5y^2-20y-8z+2yz$.

Factorise the expression$10ab+4a+5b+2$.

Write the factorised form of $6xy-4y+6-9x$

If $a^4-b^4$  can be expressed as $\left(a-b\right)\left(k\right)\left(a^2+b^2\right)$, then $k$ is

If $p^4-81$ can be written as $\left(p-3\right)\left(k\right)\left(p^2+9\right)$ then which of the following is $k$?

If $x^4-{\left(y+z\right)}^4$ can be factorised as $\left(x+y+z\right)\left(x-y-z\right)\left(x^2+{\left(y+z\right)}^m\right)$, then what is the value of $m$?