Given the two ordered pairs (1,-2), and (3,-8), how do you write the equation of then line in slope intercept form?

1 Answer
Alan P.
Jul 1, 2015

y = -3x+1

Explanation:

The slope for a line passing through (1,-2) and (3,-8) is
color(white)("XXXX")m = (Delta y)/(Delta x) = ((-8)-(-2))/(3-1) = -3

For a general point (x,y) on this line the slope is
color(white)("XXXX")(y-(-2))/(x-1)

Since the slope is constant for a straight line
color(white)("XXXX")(y+2)/(x-1) = -3
rArr
color(white)("XXXX")y+2= -3x+3
rArr
color(white)("XXXX")y = -3x+1
color(white)("XXXX")color(white)("XXXX")which is the slope-intercept form
color(white)("XXXX")color(white)("XXXX")with slope (-3)
color(white)("XXXX")color(white)("XXXX")and y-intercept 1

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