$9>-2-x$

$sinh\left(x-y\right)\:=\:sinh\left(x\right)cosh\left(y\right)\:-\:cosh\left(x\right)sinh\left(y\right)$

$-2r^2-40r-2=0$

$18-x<21x-26$

$\int\frac{x^3}{\sqrt{\left(x^2+81\right)}}dx$

$b\left(x^{2}a-6x^{3}a^{2}b-4x^{3}a\right)=x^{2}a$

$\int sen\left(2x-5\right)dx$