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

$$16\cdot\left(-15\right)+\left(-16\right)\cdot\left(-5\right)$$

$$4987.19-0.03$$

$$e^4+\:e^4x$$

$$\sec\left(x-50\right)=2.15$$

$$f\left(x\right)=\frac{3}{x^2-x-2}$$

$$6x^2-7x-20$$