$$\left(\frac{2}{5}x+\frac{3}{2}y\right)^2$$

$$x-12;\:x=-5$$

$$2sinx+cscx=0$$

$$-\tan^2\left(x\right)=\left(1+\sec\left(x\right)\right)\cdot\left(1-\sec\left(x\right)\right)$$

$$\left(-5x^2\right)\cdot\left(4x^4\right)+2x^3\cdot\left(-5x\right)\cdot\left(x^3\right)$$

$$\:6x^4\left(6+y^3\right)^3$$

$$\frac{1}{x-4}+\frac{1}{x+4}=\frac{16}{x^2-16}$$