$\left(2a+3c^2\right)^2$

$\lim_{x\to0}\left(\frac{sin21x}{x}\right)$

$\sqrt{9\left(-1\right)+18}$

$\frac{d}{dx}13^x$

$\frac{\cos\left(x\right)^2}{\sin\left(x\right)}+\cos\left(x\right)\cdot\tan\left(x\right)=\csc\left(x\right)$

$6x+2+1-4x+x^3+x^3-7x^3$

$\left(10y+x\right)\left(10y-x\right)$