(1) x/3:4/5=5:4
x/3*5/4=5/4
5x/12=5/4两边同乘以12
5x=15,x=3
(2) 4.5:9/7=2.5:(1-x)
4.5*7/9=2.5/(1-x)
7/2=5/(2-2x)交叉相乘
10=7*(2-2x)
1-x=5/7
x=2/7
(1) x/3:4/5=5:4
x/3*5/4=5/4
5x/12=5/4两边同乘以12
5x=15,x=3
(2) 4.5:9/7=2.5:(1-x)
4.5*7/9=2.5/(1-x)
7/2=5/(2-2x)交叉相乘
10=7*(2-2x)
1-x=5/7
x=2/7