Разложите на множители:

\(\displaystyle u\,(6x+d\,)+42lx+7dl=\)\(\displaystyle u\,(6x+d\,)+\)[ ]\(\displaystyle \big(\)[ ]\(\displaystyle \big)=\big(\)[ ]\(\displaystyle \big)\big(\)[ ]\(\displaystyle \big)\)