$43\cdot16$

$\frac{d}{dx}\frac{y+4}{x+3}$

$5a+7b-3c+b+5c+2a$

$\frac{-20x^2-19+4x+16x^4}{-2x^2+4}$

$4^4\cdot10^4$

$\left(-5\right)^{2}\left(-6\right)^{\left(-5+5\right)}+\left(-3\right)+\left(+\right)-\left(+3\right)\left(-2\right)$

$\left(\frac{5}{7}b-\frac{1}{7}c\right)^2$