$$\:\left(-4\right)\:-\:12\:-\:\left(-2\right)$$

$$5-\left(-21\right)$$

$$7.08+2.45+15.220$$

$$\cos2x=-\frac{\sqrt{3}}{2}$$

$$14ab2c-23ab2c$$

$$\int\frac{\left(2x+1\right)}{\left(x^2+3x-10\right)}dx$$

$$\frac{1}{1-sin}+\frac{1}{1+sin}$$