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

1 Answer
May 25, 2016

Slope: 1/313

Explanation:

Two ways to determine the slope for a question like this one.

Method 1: convert the given equation into slope-intercept form.
An equation in the form:
color(white)("XXX")y=color(green)(m)x+color(blue)(b)XXXy=mx+b
is in "slope-intercept form" with a slope of color(green)(m)m and a y-intercept of color(blue)(b)b

Given
color(white)("XXX")-x+3y=-12XXXx+3y=12

color(white)("XXX")3y=x-12XXX3y=x12

color(white)("XXX")y=color(green)(1/3)x+color(blue)(""(-6))XXXy=13x+(6)

Method 2: less common for some reason
Given an equation in the form
color(white)("XXX")Ax+By=CXXXAx+By=C
the slope is color(red)(-A/B)AB

For the given example
color(white)("XXX")A=(-1)color(white)("XX")andcolor(white)("XX")B=3XXXA=(1)XXandXXB=3