Intercepts and the Cover-Up Method

Key Questions

  • What are the intercepts for horizontal and vertical line graphs?

    Answer:

    #color(blue)("Horizontal line " x = a#

    #color(purple)("Vertical line " y = b#

    Explanation:

    https://www.onlinemathlearning.com/forms-linear-equations.html

    Refer table above.

    #"Equation of a line in" color(red)("Intercept Form") "is given by"#

    #x / a + y / b = 1, " where a in x-intercept and b the y-intercept"#

    For a horizontal line, y = 0 or y/b = 0 and the equation becomes,

    #x / a = 1 " or " x = a#

    Similarly, for a vertical line, x = 0 or x / a = 0 and the equation becomes,

    #y / b = 1 " or " y = b#

    sankarankalyanam · 1 · Apr 14 2018
  • How do you use the cover-up method to solve for the x and y intercept?

    I suppose that "cover-up" is a friendlier term for "setting a variable equal to zero," so if you are looking for the #x#-intercept of a line, then set #y# equal to zero, and for #y#-intercept, set #x#-equal to zero.

    Example

    Let us find the #x,y#-intercepts of the line

    #2x+3y=12#.

    To find the #x#-intercept, set #y=0#.

    #=> 2x+3(0)=12 => 2x=12 => x=6#

    So, the #x#-intercept is #6#.

    To find the #y#-intercept, set #x=0#.

    #=> 2(0)+3y=12 => 3y=12 => y=4#

    So, the #y#-intercept is #4#.

    I hope that this was helpful.

    Wataru · 1 · Nov 2 2014

Questions

Graphs of Linear Equations and Functions