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

$e^{3\left(\frac{2x}{x^2-1}\right)}-2$

$-4+5-6+7-3+6-9+4-5$

$\left(-x+b\right)^7$

$\frac{4x+3}{x^2-25}+\frac{2-3x}{x^2-25}$

$\left(m+n-7\right)\left(m+n+7\right)$

$x\left(2x+5\right)^8$