\(a)\) \(18{x^2}{y^2}z:6xyz\) \( = \left( {18:6} \right)\left( {{x^2}:x} \right)\left( {{y^2}:y} \right)(z:z) \)\(= 3xy\)
\(b)\) \(5{a^3}b:\left( { - 2{a^2}b} \right)\) \( = 5:\left( { - 2} \right)\left( {{a^3}:{a^2}} \right)\left( {b:b} \right)\)\( =\displaystyle - {5 \over 2}a\)
\(c)\) \(27{x^4}{y^2}z:9{x^4}y\) \( = \left( {27:9} \right)\left( {{x^4}:{x^4}} \right)\left( {{y^2}:y} \right).z \)\(= 3yz\)
