3.7x0.58+0.37x4.2=3.7x0.58+3.7x0.42=3.7x（0.58+0.42）=3.7x1=3.7
3.7
原式=3.7×0.58+3.7×0.42=3.7×(0.58+0.42)=3.7×1=3.7
3.7×0.58+0.37×4.2 =3.7×0.58+3.7×0.42 =3.7×(0.58+0.42 )=3.7×1=3.7
