$16\left(y-x\right)$

$9b+4b$

$36 x ^ { 6 } + 84 x ^ { 3 } + 49$

$\lim_{x\to0}\left(\frac{\sqrt{7-x}-\sqrt{7+x}}{x}\right)$

$\left(+8\right)-\left(-10\right)-\left(+12\right)$

$\frac{d}{dx}\left(x^x\right)\left(3x^3+2\right)\left(x^2+5\right)^3$

$\frac{d}{dx}\left(6x^2+4y^2=36\right)$