$$2^3+5x^2-6x+7$$

$$\lim_{x\to\infty}\:\left(1+-\frac{x^2+3x}{x^3}\right)^x$$

$$2\left(x+2y\right)^2+7x\left(x+2y\right)+5x^2$$

$$\frac{4}{x+3}\left(by\:x-1\right)$$

$$\frac{x}{2}+3>15$$

$$\int e^{1-3t}dt$$

$$a^2+5^2$$