$-10\left(-4\right)\left(-2\right)$

$f\left(x\right)=\frac{3x^2}{5x}$

$3\cdot2^4-5\cdot2^2-1$

$\lim_{x\to4}\left(\frac{4-x}{\sqrt{x}-2}\right)$

$\int\left(8x^4+4x^3-6x^2-5x+1\right)dx$

$100c^2-180+81$

$2\cos\left(x\right)\cos\left(y\right)=cos\left(x+y\right)+\cos\left(x-y\right)$