$$2\tan\left(x\right).\cos^2\left(x\right)+1$$

$$\left(7-x\right)\left(49+7x+x^2\right)$$

$$2\ln\left(x\right)-\ln\left(2x-9\right)=\ln\left(5x\right)-\ln\left(x-4\right)$$

$$\sqrt{\frac{5x}{3}}$$

$$\int\:\frac{x^6}{2\sqrt{16+x^2}}dx$$

$$\cos\left(3x\right)=0.5$$

$$9x=135$$