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21 votes
21 votes
how do u write the equation of the line that passes through the points (3,-5) and (1,-9). I have to put it in fully reduced point-slope form unless it's a vertical or horizontal line

User Matt Spoon
by
2.8k points

1 Answer

17 votes
17 votes

We have to calculate the equation of the line in slope-point form:


y-y_1=m(x-x_1)

The information we have is two points: (3,-5) and (1,-9).

First, we use one point to fill the spaces for (x1,y1). We pick (3,-5), but any of both will do.

Then we have:


y+5=m(x-3)

We will replace x and y with the coordinates of the second point (1,-9) in order to calculate the slope:


\begin{gathered} (-9)+5=m(1-3) \\ -4=m\cdot(-2) \\ m=(-4)/(-2) \\ m=2 \end{gathered}

Then, the equation becomes:


y+5=2(x-3)

User Nitish
by
2.6k points
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