Determining the value of r?

determine the value of r so the line that passes through each pair of points has the given slope? thats the directions, (1,r),(1,-4),m=-5, (-2,1),(r,4),m=3/5, (-1,3),(-3,r)m=-3? pleez explain in full detail how to answer those three questions!!PLEEEZ HELP ME!!!

1 Answer

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  • 1 decade ago
    Best Answer

    No.2

    (-2,1),(r,4), m=3/5

    Slope =m = rise/run

    3/5=(4-1)/(r-(-2))

    3/5=3/(r+2)

    3(r+2)=3(5)

    3r+6=15

    3r=9

    r=3

    N0.3

    (-1,3),(-3,r), m= -3

    -3=(r-3)/(-3-(-1))

    -3=(r-3)/-2

    (-3)(-2)=r-3

    6=r-3

    9=r

    No.1

    I've left this one to the last because, as worded, it is not possible to

    solve. There is a contradiction.

    m=rise/run,

    For (1,r),(1,-4), m=5

    5=(-4-r)/1-1)

    5=(-4-r)/0

    Division by zero is not allowed

    Therefore slope cannot be =5

    Check the co-ordinates. If they are as you say, no solution. If there is

    an error, solve as shown for Nos. 2 and 3.

    As it stands, the coordinates (1,r)(1,-4) lie on a horizontal line r+4 units

    above (or below, if r<-4) the x-axis

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