How do you write an equation of a line with Slope =3,(4,-8)?

1 Answer
Alan P.
Jun 26, 2015

#y+8=3(x-4)#
or in standard form #3x -1y = 20#

Explanation:

Given a slope of #m=3# through a point #(hatx,haty)= (4,-8)#
the slope-point form of a line:
#color(white)("XXXX")##(y-haty) = m (x-hatx)#
becomes
#color(white)("XXXX")##y-(-8) = 3 (x-4)#
or
#color(white)("XXXX")##y+8 = 3(x-4)#

While this is a perfectly correct answer, an equation in standard form might be more desirable.

#color(white)("XXXX")##y+8= 3x -12#

#color(white)("XXXX")##-3x+y+8 = -12#

#color(white)("XXXX")##-3x+y = -20#

#color(white)("XXXX")##3x-y = 20# (in standard form)

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