How do you graph x - 2/3y = 1 x23y=1?

1 Answer
May 30, 2017

First, let's rewrite this as point-slope form or y=mx+by=mx+b:

x-2/3y=1x23y=1

subtract xx on both sides

-2/3y=1-x23y=1x

divide both sides by -2/323

y=(1-x) -: -2/3y=(1x)÷23

y= (1-x)/1 xx -3/2y=1x1×32

y= (2(-x+1))/3y=2(x+1)3

y=(-2x+2)/3y=2x+23

y=-(2)/3x + 2/3y=23x+23
Now it's in point-slope form ( y=color(red)(m)x+color(blue)(b)y=mx+b )

the reason I wanted it in this exact form is because it gives us valuable information: the color(red)(slope)slope and the color(blue)(y-i ntercept)yintercept

These are very helpful for graphing, buecause we really only need to points on the line to draw the rest of it. And we already have one, the yy-intercept:

y=color(red)(-2/3)x+color(blue)(2/3)y=23x+23
The yy-intercept is (0, 2/3)(0,23), and it's very simple to find the xx-intercept. All we need to do is set yy equal to zero and solve for xx:

y=-(2)/3x + 2/3y=23x+23

0=-(2)/3x + 2/30=23x+23

subtract 2/323 on both sides

-2/3=-2/3x23=23x

divide by -2/323 on both sides

-2/3 -: -2/3 = x23÷23=x

cancel-cancel2/cancel3 xx cancel-cancel3/cancel2 = x

x=1

So, now we have two pints: (0, 2/3) and (1, 0). Now you just need to use a rule to draw a line between these points, or start at one of them and use the slope to find more points:

Just to check our work, let's graph our equation. If we did everything correctly, the line should pass through the points (0, 2/3) and (1, 0).

graph{y=-(2)/3x + 2/3}

We were right!