Find the product of the following:

$(x+8)(x-5)$

Find the product of the following:

$(3 x-8)(5 x-1)$

Find the product of the following:

$(x-5 y)(x+10 y)$

Find the product of the following:

$\left(5a^2-4b^2\right)\left(\frac{1}{5}a-\frac{1}{4}b\right)$

Find the product of the following:

$\left(3p^2+q^2\right)\left(p^2+2q^2\right)$

Find the product of the following:

$\left(4a+\frac{3b}{5}\right)\left(3a-\frac{4b}{5}\right)$

Find the product of the following:

$\left(\frac{x}{2}-\frac{x^2}{3}\right)\left(\frac{y^2}{9}-\frac{y}{7}\right)$

Find the product of the following:

$\left(2x^2+5y^2\right)\left(6x^2-15y^2\right)$

Find the product of the following:

$(x-y)\left(x^2+xy+y^2\right)$