Q:

Write the equation, in slope-intercept form, of the line passing through the origin and the point $(-4,3)$.

Accepted Solution

A:
If the equation is passing trough the origin, it will be passing trough the point (0,0). We now for our problem that the equations is also passing trough the point (-4,3). So, our line is passing trough the points (0,0) and (-4,3). To write the equation in slope-intercept form, first, we need to find its slope [tex]m[/tex]. To do that we are going to use the slope formula: [tex]m= \frac{y_{2}-y_{1}}{x_{2}-x_{1}} [/tex].
From our two points we can infer that [tex]x_{1}=0[/tex], [tex]y_{1}=0[/tex], [tex]x_{2}=-4[/tex], [tex]y_{2}=3[/tex]. Lets replace those values in the slope formula:
[tex]m= \frac{y_{2}-y_{1}}{x_{2}-x_{1}} [/tex]
[tex]m= \frac{3-0}{-4-0} [/tex]
[tex]m= \frac{3}{-4} [/tex]
[tex]m=- \frac{3}{4} [/tex]

Now that we have our slope, we can use the slope-intercept formula:
[tex]y-y_{1}=m(x-x_{1})[/tex]
[tex]y-0=- \frac{3}{4} (x-0)[/tex]
[tex]y=- \frac{3}{4} x[/tex]

We can conclude that the equation of the line passing trough the points (0,0) and (-4,3) is [tex]y=- \frac{3}{4} x[/tex].