If 3x + 7y = 12 and x-y= 1, then what is the value of 5x + 5y?

Question

If 3x + 7y = 12 and x-y= 1, then what is the value of 5x + 5y?

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Thiên Hương 4 years 2021-08-15T22:51:42+00:00 1 Answers 8 views 0

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  1. Calantha
    0
    2021-08-15T22:52:48+00:00
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    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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