方程 9分之8-x=6分之5 17分之3+x=17分之5 x-39分之4=13分之5 4-x=7分之2

题目

方程 9分之8-x=6分之5 17分之3+x=17分之5 x-39分之4=13分之5 4-x=7分之2
列示计算 两个数的和是8分之7,一个数加数是9分之7,另一个加数是多少?2分之1与3分之1的和比一个数少6分之1,这个数是多少?

答案

8/9 - x = 5/6
x = 8/9 - 5/6
x = 16/18 - 15/18
x = 1/18
3/17 + x = 5/17
x = 5/17 - 3/17
x = 2/17
x - 4/39 = 5/13
x = 5/13 + 4/39
x = 15/39 + 4/39
x = 19/39
4 - x = 2/7
x = 3+ 7/7 - 2/7
x = 3+ 5/7
x = 3又5/7
7/8 - 7/9
= 63/72 - 56/72
= 7/72
1/2 + 1/3 + 1/6
= 3/6 + 2/6 + 1/6
= 6/6
= 1