$\sec\left(x\right)=\frac{\sec^2\left(x\right)-\tan^2\left(x\right)}{\sec\left(x\right)+\tan\left(x\right)}+\tan\left(x\right)$

$\left(-1\right)-\left(-2\right)+\left(-3\right)+\left(+2\right)$

$\frac{\sin^2+\cos^2}{\cos}=\sec$

$\left(a-3\right)\left(a+4\right)$

$\frac{\left(x^3-4x^2+5x-2\right)}{x}$

$54+31+7n^2-\:n^2$

$82c^2-16y^2$