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What is the y-intercept form for the two points (0, -1) and (3,-2) if their relationship is proportional?

Guest Oct 26, 2017

Best Answer 

 #1
avatar+5198 
+1

I think you want the slope-intercept form for the equation of a line that passes through these points.

 

slope intercept form is:     y = mx + b     , where  " m "  is the slope and  " b"  is the y-intercept.

 

slope  =  \(\frac{\text{change in y}}{\text{change in x}}\,=\,\frac{y_2-y_1}{x_2-x_1}\,=\,\frac{-2-(-1)}{3-0}\,=\,\frac{-2+1}{3}\,=\,-\frac13\)

 

→    m  =  - \(\frac13\)

 

Since  (0, -1)  is a point on the line, we know that when  x = 0 ,  y = -1  .   So...

 

the y-intercept  =  -1

 

→    b  =  -1

 

So our equation is

 

y  =  - \(\frac13\)x  - 1

hectictar  Oct 26, 2017
edited by hectictar  Oct 26, 2017
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1+0 Answers

 #1
avatar+5198 
+1
Best Answer

I think you want the slope-intercept form for the equation of a line that passes through these points.

 

slope intercept form is:     y = mx + b     , where  " m "  is the slope and  " b"  is the y-intercept.

 

slope  =  \(\frac{\text{change in y}}{\text{change in x}}\,=\,\frac{y_2-y_1}{x_2-x_1}\,=\,\frac{-2-(-1)}{3-0}\,=\,\frac{-2+1}{3}\,=\,-\frac13\)

 

→    m  =  - \(\frac13\)

 

Since  (0, -1)  is a point on the line, we know that when  x = 0 ,  y = -1  .   So...

 

the y-intercept  =  -1

 

→    b  =  -1

 

So our equation is

 

y  =  - \(\frac13\)x  - 1

hectictar  Oct 26, 2017
edited by hectictar  Oct 26, 2017

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