slope is – 2/7 and the x-intercept is ( – 7 , 0 )

Question

Find the equation of the line in the form ax+by=c

Answer 1

You should, once and forever, convert the Standard Form of the equation of a line (Ax+By=C) to slope-intercept form (y=mx+b) and remember that:

        slope = (-A/B)

        y-intercept = (C/B)             [the place where x=0]

 

Also, the x-intercept (the place where y=0) is (C/A).

 

Use (-2/7) as (-A/B) and use (-7) as (C/A):

    A = 2

    B = 7

    C = -14      [note that A is 2 and (-14/2) = (-7)]

 

The equation in Standard Form is:    2x + 7y = -14

 

 

Answer 2

Use Y-y1 = m (X - x1), the point slope formula.  Y - 0 = -2/7 (X +7) which is Y = -2/7X - 2. Multiply both sides by 7 to get 7Y = -2X - 14 and add 2X to both sides to get   2X + 7Y = -14