`a)(-7/2)+ (-2/3)+ (-3/5)`
`=(-105/30)+(-20/30)+(-6/30)`
`=-131/30`
`b)(-1/4+1/5):(49/48-1,25)`
`=(-5/20+4/20):(49/48-5/4)`
`=-1/20:(49/48-60/48)`
`=-1/20:(-11/48)`
`=-12/55`
`c)2/7-24/12:3/5`
`=2/7-2 . 3/5`
`=2/7.(-6/5)`
`=-12/35`
`d)-5/7+1/7.(3/4-5/1)`
`=-5/7+1/7.(3/4-20/4)`
`=-5/7+1/7.(-17/4)`
`=-5/7+17/28`
`=-20/28+17/28`
`=-3/28`
`e)7/8:(2/9-1/8)+7/8:(1/36-5/12)`
`=7/8:(16/72-9/72)+7/8:(1/36-15/36)`
`=7/8:7/12+7/8:(-14/36)`
`=7/8:[21/36+(-14/36)]`
`=7/8:7/36`
`=9/2`