Question 53646: determine the equation of the line passing through the points (-2, 5), (8,-9), and (0,1).
Answer by funmath(2933)   (Show Source):
You can put this solution on YOUR website! If you are in aglebra, these points (-2,5),(8,-9),(0,1), don't lie exactly on the same line. Get Some graph paper, plot the points and see for yourself. If your being asked for a linear regression line, let me know and I'll show you that.
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Algebraically you can find the equation of the line by taking two points (x1,y1) and (x2,y2) and plugging them into the slope (m) formula:
Let's use (0,1) as (x1,y1) because it's the easiest and it's the y-intercept.
Let's use (8,-9) as (x2,y2), No reason, you can pick either of the remaining points.
Now we have a slope (m=-5/4) and a y intercept (0,b)=(0,1)
Use the slope intercept form: y=mx+b and you get:
y=(-5/4)x+1
If you're only being asked for a close fit, that's probably good enough. But if they want a line that actually goes through all three points. You can check the third point (-2,5)and find out it's not on the same line as the other two.
5=(-5/4)(-2)+1
5=5/2+1
5=7/2
That's not true, so it's not actually on that line.
Like I said though, without actually seeing what you're going over, I can't tell if you're just supposed to get a close fit. If so, this is close. If you're supposed to get a linear regression line, that's a little more complicated, but I can show you that as well.
I hope that helped.
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