$\frac{x+4}{4}+\frac{x+5}{4}$

$\frac{db}{dt}+2b=50,\:b\left(1\right)=60$

$\ln x^3-\ln x^2=\frac{1}{2}$

$4\cos\left(g+30\right)+2\sin\left(g\right)$

$\lim_{x\to4.01}\left(\frac{x^2-16}{x+4}\right)$

$\:\left(2x+7y\right)\left(2x-7y\right)$

$16x^4\:+\:2x^3+\:12x^2+\:4x$