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math need help

posted by .

study time in X hours
8
5
7
12
10

test grade Y in percent
68
50
62
92
80
a)model the date in a linear function
b)interpret the meaning of the slope

  • math need help -

    5 , 50

    7 , 62

    8 , 68

    10 , 80

    12 , 92


    Different :

    7 - 5 = 2

    62 - 50 = 12

    12 / 2 = 6

    That mean :

    y increases for 6 when x increases for 1

    That is slope.


    Slope intercept equation of straight line :

    y = m ( x + x1 ) + y1


    In this case :

    m = ( y2 - y1 ) / ( x2 - x1 )

    You can take any two points , example:

    x1 = 8

    y1 = 68

    x2 = 10

    y2 = 80


    m = ( y2 - y1 ) / ( x2 - x1 )

    m = ( 80 - 68 ) / ( 10 - 8 ) = 12 / 2 = 6

    Slope = 6


    y = m ( x - x1 ) + y1

    y = 6 ( x - 8 ) + 68

    y = 6 x - 48 + 68

    y = 6 x + 20


    Proof :

    x = 8

    y = 6 * 8 + 20 = 48 + 2 = 68


    x = 5

    y = 6 * 5 + 20 = 30 + 20 = 50


    x = 7

    y = 6 * 7 + 20 = 42 + 20 = 62


    x = 12

    y = 6 * 12 + 20 = 72 + 20 = 92


    x = 10

    y = 6 * 10 + 20 = 60 + 20 = 80

  • math need help -

    i need help on my math work

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