$\left(3y\right)\left(y^2\right)$

$\frac{-0.4}{x}+0.8=1.2$

$\lim_{x\to0}\left(\frac{sin^2\left(5x\right)}{x}\right)$

$100x^4+100x^2+25$

$\frac{x+1}{x^2-4x+4}+\frac{4}{x^2+3x-10}$

$\left(11x^2-6y^2-5\cdot\left(-\frac{1}{3}\cdot x+\frac{13}{9}\cdot y+13\right)\right)\cdot39$

$6a\left(m-n\right)-3b\left(m-n\right)-3m+3n$