$$a^2-6a-91=0$$

$$2x\left(x-3\right)\le1$$

$$\int x^nin\left(x\right)dx$$

$$\lim_{x\to0}\left(x+1\right)^{\sec\left(\frac{\pi}{2}-x\right)}$$

$$\left(\left(x+a\right)-3\right)\left(\left(x+a\right)+3\right)$$

$$-\frac{1236}{8}-\frac{56}{5}+23+36.487+\frac{781}{4}-56$$

$$a^2+3a^2+8a^2$$