`x-5/6 = 16/42 + (-8)/56`
`x-5/6=8/21 - 1/7`
`x-5/6 = 8/21 - 3/21`
`x-5/6=5/21`
`x=5/21+5/6`
`x=15/14`
______________________
`x+7/8=13/12`
`x=13/12-7/8`
`x=26/24-21/24`
`x=(26-21)/24`
`x=5/24`
_______________________
`x/15 = 19/15`
`x=19/15 xx 15`
`x=(19xx15)/15`
`x=19`
_________________
`x+4/5=6/20-(-7/3)`
`x+4/5=6/20+7/3`
`x+4/5=79/30`
`x=79/30-4/5`
`x=79/30 - 24/30`
`x=11/6`
______________________
`-7/5-x=-4/9`
`x=-7/5-(-4/9)`
`x=-7/5+4/9`
`x=-63/45+ 20/45`
`x=-43/45`