1.4 Lösning 3a

\( {20\,x^3\,y^2 \over 4\,x^2\,y} \) \( = \) \( {5\,x^3\,y^2 \over x^2\,y} \) \( = \) \( {5\,x\,y^2 \over y} \; = \; 5\,x\,y \)