$\frac{3\left(a-b\right)}{9}+\frac{4b}{9}$

$\lim_{x\to\infty}\left(\frac{\left(2-\left(4x^2+4x\right)\right)}{3x-2x^2+1}\right)$

$k^2+10k+25$

$\frac{d}{dx}\left(\frac{\left(\left(x\right)^x\left(x+1\right)^4\right)}{e^{\sqrt{x}}}\right)$

$ln\left(x.y\right)=12.733$

$x^3+5x^2-17x-21$

$4=7+c$