$6b\:+\:4r\:+\:8$

$49m^6-70am^3n^2+25a^2n$

$y=\frac{x^2+6x}{10-x^2}$

$\lim_{x\to0}\left(\frac{x^3+\sin^3\left(kx\right)}{x^2+\sin^2\left(kx\right)}\right)$

$-4\left(2a-3\right)$

$\lim_{x\to0}\left(\frac{1-x-lnx}{x^3-3x+2}\right)$

$\log_{\frac{1}{2}}\left(x^2-4x+11\right)=-3$