$-2\sqrt{7}+5\sqrt{7}-8\sqrt{7}+3\sqrt{7}+5\sqrt{7}+7\sqrt{7}$

$\frac{1}{cot^2x}+sec\left(x\right)cos\left(x\right)$

$\frac{4}{5}x^2+\frac{7}{5}x^2+\frac{1}{5}x^2$

$\int\left(\frac{8x}{4+x^2}\right)dx$

$\frac{\tan\left(a\right)}{\cos^2\left(a\right)}=\frac{1+\tan^2\left(a\right)}{\cot\left(a\right)}$

$\lim_{x\to0}\left(\frac{ln\left(5x\right)}{\frac{1}{sqrt\left(x\right)}}\right)$

$\left(64-c^3\right)\left(4-c\right)$