Đáp án+Giải thích các bước giải:
a)
`2(7x+10)+5=3(2x-3)-9x`
`<=>14x+20+5=6x-9-9x`
`<=>14x+25=-3x-9`
`<=>14x+3x=-9-25`
`<=>17x=-34`
`<=>x=-2`
Vậy `S={-2}`
c)
`x/30+(5x-1)/10=(x-8)/15-(2x+3)/6`
`<=>(x+3(5x-1))/30=(2(x-8)-5(2x+3))/30`
`<=>x+3(5x-1)=2(x-8)-5(2x+3)`
`<=>x+15x-3=2x-16-10x-15`
`<=>16x-3=-8x-31`
`<=>16x+8x=-31+3`
`<=>24x=-28`
`<=>x=-7/6`
Vậy `S={-7/6}`