$\left(\frac{3}{4}m^2n-\frac{5}{9}mn^2\right)^2$

$\left(x+y\right)^2-2\left(x+y\right)\left(x-y\right)+\left(x-y\right)^2$

$2\cdot13+2\left(-13\right)$

$\left(\sec\left(x\right)\right)^2+\sec\left(x\right)\cdot\tan\left(x\right)=\frac{1}{1-\sin\left(x\right)}$

$-0.25x^2+2x+1$

$x^2+8x+3\ge12x+24$

$4\left(1-x^2\right)\frac{dy}{dx}\:=\:2x^3y\left(y+1\right)$