Đáp án+Giải thích các bước giải:
f) `2/7-3/4+5/7+-1/4+3/5`
` =(2/7+5/7)+(-3/4-1/4)+3/5`
`=1-1+3/5`
`=3/5`
g) `5/(1*3)+5/(3*5)+5/(5*7)+...+5/(99*101)`
`=5.[2/(1*3)+2/(3*5)+2/(5*7)+...+2/(99*101)]`
`=5/2.[(2-2/3)+(2/4-2/5)+(2/4-2/5)+(2/99-2/101)]`
`=5/2.(2-2/101)`
`=5/2.(200)/101`
`=500/101`
`#Study well`