$\frac{\sqrt{3}\cdot\cos\left(20\right)}{\sin\left(80\right)}-\frac{\sin\left(20\right)}{\sin\left(80\right)}=x$

$\left(d+1\right)\left(5-d\right)$

$\int\sin^2\left(6x\right)\cos^5\left(6x\right)dx$

$\left(x-30\right)\left(x+6\right)$

$\int\frac{4x}{\sqrt{x^2-81}}dx$

$\frac{x^3+2ax^2+bx+5}{x^2+3x+2}$

$\int\frac{1}{\left(7x+8\right)^6}dx$