$#Đáp án+Giải thích các bước giải:$
`1/2x + 3/5(x-2) = 3`
`=>1/2x + 3/5x -3/5*2 = 3`
`=>1/2x + 3/5x - 6/5 =3`
`=>1/2x + 3/5x = 3 + 6/5`
`=>(1/2+3/5)x=21/5`
`=>11/10x=21/5`
`=>x = 21/5:11/10`
`=> x = 42/11`
Vậy `x =42/11`
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