$\lim\:_{y\to\:0}\left(\frac{1-\sqrt{1-4y\left(x-y\right)}}{2y}\right)^2$

$\:2\left(-15j+6\right)$

$\left(5n-\frac{4}{5}\right)\left(5n-\frac{1}{5}\right)$

$2w^2-w-1$

$_{x\to\:\infty\:}\left(\sqrt{x^2+x}-x\right)$

$\int_0^{\infty}\left(\frac{e^x}{e^2x+3}\right)dx$

$\lim_{x\to5}\left(\frac{9x^2-41x-20}{x-5}\right)$