Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

Algebra 1 Help Fill In extras?

Okay the points are (-2,-1) and 7,-4 Can someone please find the y and x intercepts and slope intercept form and standard form and point slope form?

Ill vote best answer to first who finds those or most of them.

Thanks.

5 Answers

Relevance
  • Novy
    Lv 5
    1 decade ago
    Favorite Answer

    Best thing to do is first find the slope of the line:

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

    m = (-4 + 1) / (7 + 2)

    m = -3/9

    m = -1/3

    Next, we want to do point-slope form:

    (y - y1) = m(x - x1)

    y + 1 = (-1/3)(x + 2)

    Next we want to solve for y to get slope-intercept form:

    y + 1 = (-1/3)x - (2/3)

    y = (-1/3)x - (5/3)

    Now let's find the y-intercept. This is "b" in slope-intercept form so:

    y-intercept = (0, -5/3)

    Now let's find the x-intercept. This occurs when y=0.

    0 = (-1/3)x - (5/3)

    (1/3)x = -(5/3)

    x = -5

    So:

    x-intercept = (-5, 0)

    Standard form, take your slope-intercept form, and multiply by some clever value so there's no fraction and put in Ax + By = C:

    (3)*[y = (-1/3)x - (5/3)]

    3y = -1x - 5

    x + 3y = -5

  • 1 decade ago

    (x1, y1) = (-2, -1)

    (x2, y2) = (7, -4)

    Slope, m = (y2 - y1) / (x2 - x1) = (-4 - -1) / (7 - -2) = (-4 + 1) / (7 + 2) = -3/9 = -1/3

    y - y1 = m(x - x1)

    y - -1 = (-1/3)(x - -2)

    y + 1 = (-1/3)(x + 2)

    y + 1 = (-1/3)x - 2/3

    y = (-1/3)x - 2/3 - 1

    y = (-1/3)x - 2/3 - 3/3

    y = (-1/3)x - 5/3 <=== Slope-intercept form of the linear equation

    Based on this equation, the y-intercept is -5/3; or point (0, -5/3).

    (y + 1) = (-1/3)(x + 2) <=== point-slope form of the linear equation

    Cross-multiply:

    -3(y + 1) = (x + 2)

    -3y - 3 = x + 2

    x + 3y = -3 - 2

    x + 3y = -5 <=== Standard form of the linear equation

    To find the x-intercept, find the value of x when y = 0.

    x + 3(0) = -5

    x + 0 = -5

    x = -5 <=== the x-intercept or point (-5, 0)

  • 1 decade ago

    x1 = - 2

    y1 = - 1

    x2 = 7

    y2 = - 4

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

    m = [(- 4) - (- 1)] / (7 - (- 2)]

    m = (- 4 + 1) / (7 + 2)

    m = - 3 / 9

    m = - 1/3

    b = y - mx

    b = - 1 - [(- 1/3)(- 2)]

    b = - 1 - (2/3)

    b = - 3/3 - 2/3

    b = - 5/3

    x-int.: y = 0:

    - 1/3 x - 5/3 = 0

    - 1/3 x = 5/3

    x = (5/3) / (- 1/3)

    x = (5/3)(- 3)

    x = - 15 / 3

    x = - 5

    x-int.: (- 5, 0)

    ¯¯¯¯¯¯¯¯¯¯¯

    y-int.: x = 0:

    y = - 1/3(0) - 5/3

    y = - 5/3

    y-int. (0, - 5/3)

    ¯¯¯¯¯¯¯¯¯¯¯¯

    Slope-Intercept Form:

    y = - 1/3x - 5/3

    ¯¯¯¯¯¯¯¯¯¯¯¯¯

    Standard Form:

    1/3x + y + 5/3 = 0

    x + 3y + 5 = 0

    ¯¯¯¯¯¯¯¯¯¯¯¯¯

    Point-Slope Form:

    (y - y1) = m(x - x1)

    (y - (- 1) = - 1/3[x - (- 2)]

    (y + 1) = - 1/3(x + 2)

    ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

  • 1 decade ago

    Slope= -1/3

    y+1=-1/3(x+2)

    y=-1/3x-1/3

    y-intercept= -1/3

    x-intercept= 1

    Hope I helped!

  • How do you think about the answers? You can sign in to vote the answer.
  • 1 decade ago

    y = -1/3x - 5/3

    y-intercept = -5/3

    x-intercept = -5

    Slope-intercept form: y=mx+b

    the slope, m, is found by finding:

    (y2-y1)/(x2-x1) = (-4-(-1))/(7-(-2)) = -1/3

    So you have:

    y = -1/3x + b, where b is the y-intercept.

    To find b, plug in one of your point: (-2,-1)

    -1 = (-1/3)(-2) + b, which gives b = -5/3

    So you have:

    y = -1/3x - 5/3

    To find the x-intercept, set y=0

    0 = -1/3x -5/3

    Solving, you get x = -5

Still have questions? Get your answers by asking now.