$\:\:\:2\:\:+\:\:6a\:\:+\:\:9b\:\:-\:\:3b\:\:-\:\:a$

$\left(25a^2x-15x\right)\left(25a^2x+6x\right)$

$\lim_{x\to2}\left(3x^2-4x+1\right)$

$16x-3\:\le\:4$

$\frac{dy}{dx}=\frac{\left(2+x+y\right)}{\left(x+y-3\right)}$

$\frac{3}{2}xy^3+\frac{5}{6}xy^3+\frac{7}{3}xy^3$

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