$$\left(2a^2-4\right)\left(2a^2-7\right)$$

$$\left(\frac{2}{3}m^2x-5n^3z^2\right)^2$$

$$\cos^{-1}\left(\frac{3.7}{5.4}\right)$$

$$4x^2b+2ab+9x^2b$$

$$22^2$$

$$6x-y\cdot y'=x^2\cdot y\cdot y'-3xy^2$$

$$\lim_{x\to5}\left(\frac{\left(10x-50\right)}{x^{2}-25}\right)$$