Giải thích các bước giải:
Bài `2`
`a)`
`x+(-7/15)=-1 1/20`
`=>x-7/15=-21/20`
`=>x=-21/20+7/15`
`=>x=-63/60+28/60`
`=>x=-35/60`
`=>x=-7/12`
Vậy `x=-7/12`
`b)`
`(3 1/2-x).1 1/4=-1 1/20`
`=>(7/2-x). 5/4=-21/20`
`=>7/2-x=-21/20 : 5/4`
`=>7/2-x=-21/20 . 4/5`
`=>7/2-x=-21/25`
`=>x=7/2+21/25`
`=>x=175/30+42/50`
`=>x=217/50`
Vậy `x=217/50`
`c)`
`5,2.x+7 2/5=6 3/4`
`=>5,2.x+37/5=27/4`
`=>5,2.x=27/4-37/5`
`=>5,2.x=270/40-296/40`
`=>5,2.x=-26/40`
`=>x=-26/40:5,2`
`=>x=-1/8`
Vậy `x=-1/8`
`d)`
`2,4:(-1/2-x)=1 3/5`
`=>2,4:(-1/2-x)=8/5`
`=>-1/2-x=2,4:8/5`
`=>-1/2-x=3/2`
`=>x=-1/2-3/2`
`=>x=-4/2`
`=>x=-2`
Vậy `x=-2`
`e)`
`2.|2x-3|=50`
`=>|2x-3|=50:2`
`=>|2x-3|=25`
TH`1`
`2x-3=25`
`=>2x=25+3`
`=>2x=28`
`=>x=28:2`
`=>x=14`
TH`2`
`2x-3=-25`
`=>2x=-25+3`
`=>2x=-22`
`=>x=-22:2`
`=>x=-11`
Vậy `x\in{14;-11}`
