解:x÷7/5=4/5-1/5 x=3/5×7/5 x=21/25
x÷7/5+1/5=4/5 x÷7/5 = 4/5-1/5 x÷7/5 = 3/5x = 21/25
x÷7/5=3/5 x÷7=3 x=21
