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24 votes
24 votes
(-55,22) and (4,r) lie on a line with a slope -2 find the missing coordinate r

User Saboora
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1 Answer

10 votes
10 votes

We have a line with slope m=-2 that pass through the point (-55,22).

We then can write the slope-point equation as:


\begin{gathered} y-y_0=m(x-x_0) \\ y-22=-2(x+55) \\ y-22=-2x-110 \\ y=-2x-110+22 \\ y=-2x-88 \end{gathered}

Now we have to find the value of r when for the point in the line (4,r).

We can replace x with 4 and r with y and calculate:


\begin{gathered} y=-2x-88 \\ r=-2(4)-88 \\ r=-8-88 \\ r=-96 \end{gathered}

Answer: r=-96

User Harriv
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