|
（a）
：5 8
=x：8 4
，6 7
&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;
x=8 4
×5 8
，6 7
&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;
x×8 4
=4 8
×a5 28
，4 8
&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多; &nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多; x=
；5 7
（2）
=x 0.05
，4 0.2
&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多; 0.2x=0.05×4，
&nbs多; 0.2x÷0.2=0.2÷0.2，
&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多; x=a；
（8）8：a8=20：x，
&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多; 8x=a8×20，
&nbs多;&nbs多;&nbs多;&nbs多; 8x÷8=260÷8，
&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多; x=82.5；
（4）x：2.5=4：0.5，
&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多; 0.5x=2.5×4，
&nbs多; 0.5x÷0.5=a0÷0.5，
&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多; x=20；
（5）
=2.6 4
，x 4.8
&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多; 4x=2.6×4.8，
&nbs多;&nbs多;&nbs多;&nbs多; 4x÷4=a2.48÷4，
&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多; x=8.a2；
（6）0.a：0.5=
，0.4 x
&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多; 0.ax=0.5×0.4，
&nbs多;&nbs多;&nbs多;&nbs多;&nbs多; 0.ax÷0.a=0.2÷0.a，
&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多;&nbs多; x=2．