如果3x=4y(x,y不等于0),x:y= : ,x与y成 比例.
因为A×B=1,所以A=,B=.(A、B≠0) .
÷7=÷ =38.
× =× = ×= ×0.1=+ = ﹣.
× =× =+ =1.5× =× =1.
× =3600 × =3600 × =3600 × =3600 × =3600.