$-5xy+3yx-7xz$

$\lim_{x\to0}\left(\frac{sen\left(x\right)}{x}^{x^{-2}}\right)$

$\left(6y^2-9y^3\right)^2$

$\lim_{x\to0}\left(\frac{tan\left(e^{2x}-1\right)}{x}\right)$

$3x^2+12x$

$\log_{x-5}\left(x^2+8x-5\right)=\log_{x-5}\left(3x^2-15\right)$

$4+8+2\left(9+4\right)$