$4^2+20x+25$

$\int\frac{15x}{\left(sqrt\left(9-x^2\right)\right)}dx$

$\tan^2\left(m\right)-\sin^2\left(m\right)=\tan^2\left(m\right)\sin^2\left(m\right)$

$a+b-b+a+a+b$

$\frac{d}{dx}\:\cosh^2x-senh^2x=1$

$\lim_{x\to a}\left(\frac{x^3-ax^2-a^2x-a^3}{x^2-a^2}\right)$

$\:-\left[7+3-4-\left(7+3-4\right)\right]$