$$B=4ab^{3}\times5a^{4}; E=(-5a^{3}b)\times(-2a^{3}b^{2}c); L=-2ab^{2}\times(-a^{2}b^{3})^{3}$$
$B=20b^{3}a^{5}$
$a\in \mathrm{R}$
$b\in \mathrm{R}$
$E=10cb^{3}a^{6}$
$c\in \mathrm{R}$
$L=2a^{7}b^{11}$
