$$18-x<21x-26$$

$$\int\frac{-24x^3}{\left(x^4+2\right)^2}dx$$

$$\frac{dy}{dx}+y\cdot\sin\left(x\right)=\sin\left(x\right)$$

$$121a^2-16$$

$$9x^6-12x^4+4x^2$$

$$\sqrt{5}ab^7\sqrt{10}a^3b^3$$