$\lim_{x\to\infty}\left(\frac{\left(2n^2+6\left(2^n\right)\right)}{\left(3\left(2^n\right)-n^2+1\right)}\right)$

$2a\left(6a+7b\right)-9a\left(2a+6b\right)-7b\left(9b+2a\right)$

$m^4-a^3m-a^4+7a^2m^2-18am^3+5m^4$

$-7\left(8\right)-26$

$cos\:t\:cot\:t\:=\:\frac{1-sin^2\:t}{sin\:t}$

$12c^2d-24cd^2+6c^3d^2$

$12-\left(-52.5\right)$