$9-\left(x-2y\right)^2$

$x-5+3x-4$

$\frac{216+w^3z^6}{6+wz^2}$

$log\left(x\right)+log\left(x-5\right)=log\left(x^2-5x\right)$

$6x+6\left(x+7\right)=3\left(x+2\right)$

$\sin\left(-x\right)-\cos\left(-x\right)=\frac{1}{\sin\left(x\right)^2\cdot\cos\left(x\right)^2}$

$3a^x-2-12^x-2$