What is the slope-intercept form of this equation 3x + 9y = 18?

Question

14869 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-03-21T20:10:58

See the entire solution process below:

The slope-intercept form of a linear equation is: $y = m x + b$ $y = color(red)(m)x + color(blue)(b)$

Where $m$ $color(red)(m)$ is the slope and $b$ $color(blue)(b)$ is the y-intercept value.

Therefore we must solve this equation for $y$ $y$ :

$3 x + 9 y = 18$ $3x + 9y = 18$

$- 3 x + 3 x + 9 y = - 3 x + 18$ $-color(red)(3x) + 3x + 9y = -color(red)(3x) + 18$

$0 + 9 y = - 3 x + 18$ $0 + 9y = -3x + 18$

$9 y = - 3 x + 18$ $9y = -3x + 18$

$\frac{9 y}{9} = \frac{- 3 x + 18}{9}$ $(9y)/color(red)(9) = (-3x + 18)/color(red)(9)$

$(color(red)(cancel(color(black)(9)))y)/cancel(color(red)(9)) = (-3x)/color(red)(9) + (18)/color(red)(9)$

$y = color(red)(-1/3)x + color(blue)(2)$