$$141-41-\left(-19\right)$$

$$\left(-+1\right)^2$$

$$\frac{dy}{dx}=x\cdot cos\left(5x\right)$$

$$\lim_{x\to0}\left(\ln\left(x\right).\ln\left(1-x\right)\right)$$

$$\frac{3x^4-5x^2+8}{2x^3-5x^2}$$

$$1+\frac{1}{3n^2}-\frac{1}{n}$$

$$6a^2b^2-15a^2$$