How do you find the slope and y intercept of #-12x+3y=-60#?

1 Answer
Sep 29, 2015

Answer:

Slope: #4#
y-intercept: #-20#

Explanation:

Method 1
For a linear equation in standard form: #Ax+By=C#
#color(white)("XXX")#the slope is #m=-A/B#
In this case #A=-12# and #B=3#
#color(white)("XXX")#so the slope is #m=-(-12)/3 = 4#

The y-intercept is the value of #y# when #x=0#
Replacing #x# with #0# in the original equation:
#color(white)("XXX")-12(0)+3y =-60#
#rarrcolor(white)("XXX")3=-20#

Method 2
Alternately, you could rearrange the expression into "slope-intercept form: #y=mx+b#
(with slope #=m# and y-intercept #=b#)

Given
#color(white)("XXX")-12x+3y=-160#
Add #12x# to both sides
#color(white)("XXX")3y= 12x-60#
Divide by #3#
#color(white)("XXX")y=4x-20#
#color(white)("XXXXX") (=4x+(-20))#
which is "slope-intercept form"
with slope #m=4# and y-intercept#=-20#