Tính tích các đơn thức sau:
\(\eqalign{ & a)\,\, - 6{x^3}{y^2}\,\,\,\& \,\,\,3{x^2}yz \cr & b)\,\,{\left( {2{x^3}} \right)^3}\,\,\,\& \,\,\, - {x^2}{y^4}{z^5} \cr & c)\,\,{x^2}{y^2}\,\,;\,\,4x{y^5}z\,\,\,\& \,\,\,\left| { - 3} \right|xyz \cr}\)
\(a)\,\,( - 6{x^3}{y^2})(3{x^2}yz) = ( - 6.3)({x^3}{y^2})({x^2}yz) = - 18({x^3}{x^2})({y^2}y)z = - 18{x^{^5}}{y^3}z\)
\(b)\,\,{\left( {2{x^3}} \right)^3}( - {x^2}{y^4}{z^5}) = (8{x^9})( - {x^2}{y^4}{z^5}) = \left[ {8.( - 1)} \right]{x^9}( - {x^2}{y^4}{z^5}) = - 8({x^9}{x^2}){y^4}{z^5} = - 8{x^{11}}{y^4}{z^5}\)
\(\eqalign{ & c)\,\,({x^2}{y^2})(4x{y^5}z)(\left| { - 3} \right|xyz) = ({x^2}{y^2})(4x{y^5}z)(3xyz) \cr & = (4.3).({x^2}{y^2})(x{y^5}z)(xyz) = 12({x^2}xx)({y^2}{y^5}y)(zz) = 12{x^4}{y^8}{z^2} \cr}\)