$3\cos\left(2x\right)+1=0$

$f\left(x\right)=2x^3\left(2x^4-5x\right)$

$\frac{26m^4-36n^6}{5m^2-6n^6}$

$\left(m^2+3y\right)^5$

$\frac{\left(1+6x\right)}{\left(4x-3\right)\left(2x+5\right)}$

$\frac{25-z}{2}+\frac{z}{3}=0$

$\frac{1+\tan\:^2\left(30\right)}{\sec\:2\left(30\right)}=1$