Results 1 to 5 of 5

Math Help - Slope,equation etc. Please help

  1. #1
    Junior Member
    Joined
    Sep 2009
    Posts
    49

    Cool Slope,equation etc. Please help

    So I got this problem I had to find the midpoint,slope and distance
    for (-3,8) And (5,-2)
    I got the midpoint as (1,3)
    distance is sqr 165
    Which is what the teacher got but as for the slope
    I got he got sonething else
    I got -5 for a slope
    he got y=-5/4x + 17/4
    and I have no idea how he got that
    I just did the formula y2-y1/x2-x1

    equation of a line
    also I don't really know how to don't know how he did this
    Y=2/5x +b
    -4=2/5 (1) + b
    ans. -22/5=b
    I have no idea how he got the final ans.
    Can u please explain it as easy as possible


    Thanks
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Sep 2008
    From
    West Malaysia
    Posts
    1,261
    Quote Originally Posted by Candy101 View Post
    So I got this problem I had to find the midpoint,slope and distance
    for (-3,8) And (5,-2)
    I got the midpoint as (1,3)
    distance is sqr 165
    Which is what the teacher got but as for the slope
    I got he got sonething else
    I got -5 for a slope
    he got y=-5/4x + 17/4
    and I have no idea how he got that
    I just did the formula y2-y1/x2-x1

    equation of a line
    also I don't really know how to don't know how he did this
    Y=2/5x +b
    -4=2/5 (1) + b
    ans. -22/5=b
    I have no idea how he got the final ans.
    Can u please explain it as easy as possible


    Thanks
    HI

    you know the slope passes these 2 points ie (-3,8) and (5,-2)

    so the gradient of the slope will be

    m=\frac{-2-8}{5-(-3)}=-\frac{5}{4}

    THen to find the equation of the slope , you can use the formula

    y-y_1=m(x-x_1)

    y-8=-\frac{5}{4}(x+3)

    Can you continue ?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Sep 2009
    Posts
    1

    slope of a line

    (-3,8) , (5,-2)

    I got -5 for a slope
    he got y=-5/4x + 17/4
    and I have no idea how he got that
    I just did the formula y2-y1/x2-x1

    Gradient = y2-y1/x2-x1

    ( 8 - ( - 2 ) ) = 8 + 2 = 10
    ---------------
    . ( -3 - 5 ) . = -8

    10/-8 = -5/4 ... slope

    y = -(5/4)x + b

    insert the values of one of the sets of coordinates for x and y,
    say ( -3,8 ) to get

    8 = ((-5 *( -3 ))/4 + ( b ( the Y-intercept, the value of y when x = 0 ))

    Minus * minus = +

    8 = (15/4) + b //Subtract 15/4 from both sides,


    b = 8 - ( 15/4 )

    b = (4 * 8)/4 - 15/4 //convert 8 into quarters to give...

    b = (32 - 15)/4 = 17/4

    So the Equation of the line is...
    y = -(5/4)x +17/4


    ====================================


    The co-ordinates given are ( 1, -4 )

    -4 = ( 2/5 )*1 + b

    -4 = ( 2/5 ) + b... as before, subtract the slope from both sides

    b = -4 - 2/5

    b = -(4 * 5)/5 - 2/5 .......convert 4 into fifths to get...


    b = -20/5 - 2/5 = ( - 20 - 2 )/5

    b = -22/ 5

    So the equation of the line is ...
    y = (2/5)x - 22/5
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Junior Member
    Joined
    Sep 2009
    Posts
    49
    How do u covert # to fifith And so how
    i'm kinda having a hard tine convertin num.
    Is there a way u can explain it to me? A easy way
    oh n I will try to finish the rest mathaddict

    thank u guys so much!
    Follow Math Help Forum on Facebook and Google+

  5. #5
    A riddle wrapped in an enigma
    masters's Avatar
    Joined
    Jan 2008
    From
    Big Stone Gap, Virginia
    Posts
    2,551
    Thanks
    12
    Awards
    1
    Quote Originally Posted by Candy101 View Post
    How do u covert # to fifith And so how
    i'm kinda having a hard tine convertin num.
    Is there a way u can explain it to me? A easy way
    oh n I will try to finish the rest mathaddict

    thank u guys so much!
    Hi Candy101,

    English doesn't seem to be your first language, so I will try to explain what jizer0 did for you in one part of his explanation.

    (1) -4=\left(\frac{2}{5}\right)(1)+b

    (2) -4=\frac{2}{5}+b

    (3) -4-\frac{2}{5}=b

    Now, this is where the conversion comes in.

    In order to add or subtract fractions, you must have a common denominator. In this case that denominator is 5.

    To convert -4 to fifths, we can perform the following exercise:

    \frac{-4}{1}=\frac{x}{5}

    x=-20

    Therefore, -4=\frac{-20}{5}

    Now, continue with step (4)

    (4) \frac{-20}{5}-\frac{2}{5}=b

    (5) \frac{-22}{5}=b
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. How to find the slope of this equation?
    Posted in the Algebra Forum
    Replies: 2
    Last Post: November 28th 2011, 06:55 PM
  2. slope point equation
    Posted in the Algebra Forum
    Replies: 3
    Last Post: September 21st 2010, 08:34 PM
  3. Slope of an equation.
    Posted in the Algebra Forum
    Replies: 1
    Last Post: August 9th 2009, 05:39 PM
  4. Line equation and Slope help!
    Posted in the Pre-Calculus Forum
    Replies: 3
    Last Post: January 20th 2009, 11:32 AM
  5. equation and slope of lines
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: May 11th 2008, 12:51 PM

Search Tags


/mathhelpforum @mathhelpforum