Respuesta :

Answer:

Step-by-step explanation:

X = number of Yan's marbles.  x-3 = number of Geraldo's marbles

annswer: x + (x - 3) = 21

hopes this helps :)

Answer:

Yan has 12 marbles and Geraldo has 9

Step-by-step explanation:

Because 12 + 9 =21 and 9 is 3 less than 12.

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