Question

Find the equation (in terms of x) of the line through the points (-2,1) and (3,5)

Please include steps, I've been trying to work out problems like this and I never seem to get the correct y-intercept. I usually get the slope right, though.

Answer 1

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Answer:

y = 4/5x +13/5

Explanation:

The slope is given by the formula ...

m = (y2 -y1)/(x2 -x1)

m = (5 -1)/(3 -(-2)) = 4/5

The y-intercept is given by the formula ...

b = y -mx . . . . for any point (x, y)

b = 1 -(4/5)(-2) = 1 +8/5 = 13/5 . . . . using the first point

So, the equation is ...

y = mx +b

y = 4/5x +13/5

_____

Additional comment

If you have a bunch of these to do, you may want to make a spreadsheet with the formulas built in. Then you can type in the two points and have it spit out the m and b for your equation. Even if you don't use it to do the work, you can use it to check the work.