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Math Help - Rate of Change of Slope

  1. #1
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    Rate of Change of Slope

    For dogs that are two or more years old, the equation 5x-y+12=0 compares dog year to human years. In the equation, x represents the acutal age of a dog, and y in the age of the dog in human years.

    What rate of change does the slope represent?

    Testbook answer: 5 dog years for every human year.

    I don't why though? Can anyone help me out? Thanks.
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  2. #2
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    The rate of change in a linear function like you have is m where y=mx+c

    5x-y+12=0 \implies y=5x+12

    Can you see how m=5 in your case?
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  3. #3
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    Quote Originally Posted by pickslides View Post
    The rate of change in a linear function like you have is m where y=mx+c

    5x-y+12=0 \implies y=5x+12

    Can you see how m=5 in your case?
    I know m = 5

    But wouldn't that be 5 up 1 across on the graph? It said x is the actual dog age and y is dog's age in human years. Doesn't that mean it's 5 human years for every dog year?
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  4. #4
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    Quote Originally Posted by larry21 View Post
    I know m = 5

    But wouldn't that be 5 up 1 across on the graph? It said x is the actual dog age and y is dog's age in human years. Doesn't that mean it's 5 human years for every dog year?
    x is human years and y is dog years.

    Otherwise, a dog that is 4 dog years old would be 32 human years old, which makes no sense.
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