解:34/72+34/28等于( 425/252 )
∵已知需求出34/72+34/28等于多少
X + Y = Z
∴34/72 + 34/28
= (34×7)/(72×7)+(34×18)/(28×18)
= 238/504 + 612/504
= (238+612)/504
= 850/504
= 425/252
答:34/72+34/28等于425/252
72/34+28/34
=(72+28)/34
=100/34
=50/17
34/72十34/28=17/36+17/14=(17x7+17x18)/2x18×7=425/252=1又173/252
原式
=17/36+17/14
=17×(7/252+18/252)
=17×25/252
=425/252
=1又173/252