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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