Verified answer

Primero resuelve lo de parentecis

28 + x = 5/9 ( 60 + x )

28 + x = 300/9 + 5/9x

Agrupa a un lado las "x" y al otro terminos independientes

x - 5/9x = 300/9 - 28

9-5/9x = 300-252/9

4/9x =48/9

x = 48/9/4/9

x = 432/36

x = 12

Comprobación sustituyendo "x" en toda la ecuación

28 + x = 5/9 ( 60 + x )

28 + 12 = 5/9 ( 60 + 12 )

40 = 5/9 ( 72 )

40 = 360/9

40 = 40

28 + x = (5/9) (60 + x)

Multiplicando por 9:

9(28 + x) = 5(60 + x)

252 + 9x = 300 + 5x

9x - 5x = 300 - 252

4x = 48

x = 48/4

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x = 12

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