Respuesta :

Answer:

14.

Step-by-step explanation:

3x + 7y = 12

x - y = 1           Multiply this by -3:

-3x + 3y = -3     Add this to equation 1:

0 + 10y = 9

so y = 9/10 = 0.9.

x - 0.9 = 1

x = 1.9.

So 5x + 5y = 5*1.9 + 5*0.9

= 14.

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