$18-2x>4$

$\sin t=-\frac{8}{17}\:y\:$

$\frac{\frac{1}{1}\frac{b}{c}}{\frac{b}{c}\frac{a}{c}}$

$\frac{dy}{dx}=\left(5x^3+3x+4\right)$

$\log\left(3x+1\right)=\log\left(x-1\right)$

$\left(-4\right)^2-5\cdot\left(-4\right)-4$

$\left(n^4+16\right)\left(n^2+4\right)\left(n+2\right)\left(n-2\right)$