`(x +2)/(4 + x) = 3`
`=> (x + 2) = 3 .(4 + x)`
`=> x + 2 = 12 + 3x`
`=> x - 3x = 12 - 2`
`=> -2x = 10`
`=> x = -5`
Vậy: `x=-5`
Ta có:
\(\dfrac{x+2}{4} + x = 3\)
\(\dfrac{x+2}{4} + \dfrac{4x}{4} = \dfrac{12}{4}\)
\(x+2 + 4x = 12 \)
5x = 12 -2
5 x= 10
x = \(2\)