Expand and simplify.
$\left(-9y+7x\right)^{2}$
$\left(7-3y\right)^{2}$
$\left(5y-9\right)^{2}$
$\left(7x-2y\right)^{2}$
$\left(-8y+9x\right)^{2}$
$\left(3y-4\right)^{2}$
$\left(3y+8\right)^{2}$
$\left(-7-6y\right)^{2}$
$\left(-8x-5y\right)^{2}$
$\left(3y-7x\right)^{2}$