数学题目‘数学题目‘

x:y=8:3
设x=8k,y=3k
(1)原式=(8k-3k)/(8k+3k)=5k/11k=5/11
(2)原式=(24k+6k)/(24k-6k)=30k/18k=5/3

x:y=8:3
(x+y)(x-y)=x2-y2
x2:y2=64:9
64-9=55
(I don't know true or false.)
下一题同样！

1.5/11
2.5/3