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Someone please help me solve this math problem regarding linear functions!!?

I tried to solve it myself, but my answers didn't match up to the answers in the back of my math book, so now I'm all confused on what I did wrong. :/

Here's the problem :

Suppose your pet dog weighed 2.5 pounds at birth and 15 pounds after one year. Based on these two data points, find a linear function that describes how weight varies with age. Use this function to predict your dogs weight at 5 and 10 years of age.

6 Answers

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  • 9 years ago
    Favorite Answer

    If you were to graph weight as a function of age, you'd have the points (0, 2.5) and (1, 15). The slope is (15 - 2.5)/(1 - 0) = 12.5, and the y-intercept is 2.5; the function is y = 12.5x + 2.5.

    When x = 5, y = 12.5*5 + 2.5 = 65. When x = 10, y = 12.5*10 + 2.5 = 127.5.

  • cosano
    Lv 4
    5 years ago

    all of your given equations are linear which means that their graphs are right away lines. all of us know that if we've 2 factors, we can draw a right away line. So, that's truly what you'll do. Get 2 factors for each equation and then plot those 2 factors in a graphing paper and then connect both factors with a right away line. then you definately have your graphs. All you would possibly want to do is assign values to x and remedy for y. enable's attempt this for huge type a million) y=3x+3 even as x = a million, y = 3(a million) + 3) = 6 (a million,6) even as x = 3, y = 3(3) + 3 = 12 (3, 12) Plot (a million,6) and (3,12) in a graphing paper. connect both factors. you've your graph. enable's have yet another celebration. enable's take 9) 5x+5y=25 5y = - 5x + 25 divided by technique of 5 left and top: y = - x + 5 even as x = 2; y = -2 + 5 = 3 (2, 3) even as x = 8; y = -8 + 5 = -3 (8,-3) Plot (2, 3) and (8, - 3) in the graphing paper and connect both factors. that's your graph. i wish you may attempt this for something else. sturdy success! teddy boy

  • 9 years ago

    You can say the two data points are...

    (0,2.5) and (1,15)

    Slope = (15-2.5)/(1-0) = 12.5

    Y=mx+b

    2.5 =12.5(0)+b

    b = 2.5

    Y= 12.5x + 2.5

    So, just plug in x=5 and x=10 to predict the dogs weight...

    65....127.5...I think...

  • 9 years ago

    Let x be the number of years

    and

    y be the weight of the dog

    Consider the graph of the relationship between x and y

    Two points on this graph are already given:

    (0,2.5) and (1,15)

    Using these two points, find the slope of the graph

    slope=(15-2.5)/(1-0)

    slope=12.5

    The general equation for a linear function is:

    y=mx+b

    You have a point and the slope, so now you find the y-intercept

    Take any of the two points:

    I'll take (0,2.5) and m=12.5

    y=mx+b

    2.5=12.5(0)+b

    b=2.5

    So, the final answer is:

    y=12.5x+2.5

    hope that helped

    Source(s): me
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  • ?
    Lv 7
    9 years ago

    x = age

    y = weight

    Points given are (0,2.5) and (1,15)

    slope = 12.5

    y - 2.5 = 12.5x

    y = 12.5x + 2.5

    y(5) = 65 lb

    y(10) = 127.5 lb

  • Ian
    Lv 6
    9 years ago

    let t = 1 year

    @ t0, W = 2.5lbs

    @ t1, W = 15lbs

    15lbs/2.5lbs = 6

    W(t) = 6t

    W(5) = 6(5) = 30lbs

    W(10) = 6(10) = 60lbs

    You could also say, though, that

    W(t) = (15-2.5)t + 2.5

    W(t) = 12.5t + 2.5

    W(5) = 12.5(5) + 2.5 = 65lbs

    W(10) = 12.5(10) + 2.5 = 127.5lbs

    Sounds to me like the question is being a bit too vague to demand one answer over the other.

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