$4.9x^2-9.8x+5$

$-5a^3b+3a^3b-4a^3b+a^3b$

$\int\left(4e^{2t}\left(1+e^{2t}\right)^3\right)dt$

$20+90+51\cdot$

$2\sin\left(x\right)\cdot\tan\left(x\right)+\tan\left(x\right)=0$

$\frac{1+\cos\:\left(b\right)}{\sin\:\left(b\right)}+\frac{\sin\:\left(b\right)}{1+\cos\:\left(b\right)}=2\csc\:\left(b\right)$

$\left(x^{\frac{5}{2}}+x+x^{\frac{1}{2}}\right)^2$