Respuesta :

Answer:

The answer is x=9

Step-by-step explanation:

y = adult tickets

x = children tickets

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x + y = 15

3x + 5y = 57

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-3x - 3y = -45

3x + 5y = 57

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2y = 12

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y = 6

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x + 6 = 15

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x = 9