Respostas

2013-10-06T11:15:44-03:00
 \left \{ {{x + y = 55} \atop { \frac{x}{2} = y .  \frac{2}{7}  }} \right.

y = 55 - x

 \frac{x}{2} = 55 - x .  \frac{2}{7}

7x = 220 - 4x
7x + 4x = 220
11x = 220
x =  \frac{220}{11}
x = 20

y = 55 - x
y = 55 - 20
y = 35

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