$23\frac{1}{2}-\left(-3\frac{1}{2}\right)$

$\lim_{x\to3}\left(\frac{x^3-3x^3+3x-9}{x-3}\right)$

$\left(2m+n\right)\left(2m-9\right)$

$\left(2^3\:x\:2^{4\:x\:2}\right)$

$\lim_{t\to0}\left(\frac{\left(e^{2t}-1\right)}{\sqrt{te}}-e^2\right)$

$x^2+2x-35<0$

$121x^2-64c^2$