解由42:3/5=x:5/7
得3x/5=42×5/7
即3x/5=30
即3x=150
解得x=50.
42:3/5=X:5/7
解:3/5X=42×5/7
3/5X=30
X=30÷3/5
X=30×5/3
X=50
解:解方程,此方程的解为x = 50
∵X : Y = X ÷ Y = X / Y = Z
∴42 : 3/5 = x : 5/7
42 ÷ 3/5 = x ÷ 5/7
42 × 5/3 = x ÷ 5/7
70 = x ÷ 5/7
x = 70 × 5/7
∴x = 50
答:此方程的解为x = 50
解:42:3/5=x:5/7
3/5x=42×5/7
3/5x=30
x=30÷3/5
x=50
42:3/5=X:5/7,42x5/3=Xx7/5,X=50。