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How do you find the point slope form? (given 2 points)

2 Answers

4 votes

Answer and Step-by-step explanation:

First, define point-slope form. Point-slope form is a format of linear equations, written as: y - y1 = m(x - x1), where m is the slope and (x1, y1) is the point.

Let's say we have two points (a, b) and (c, d). We need to find the slope. Remember that slope is change in y divided by change in x. "Change in y" basically means the difference in the y-coordinates. Here, it would be: d - b. "Change in x" means the difference in the x-coordinates. Here, it would simply be c - a. So, the slope would be: m =
(d-b)/(c-a).

And, since we have two points, we can choose any of them to be our "(x1, y1)" point to use. Arbitrarily, I'm just going to choose (a, b), but you could do it with (c, d), as well. So, a = x1 and b = y1, and plug these in:

y - y1 = m(x - x1)


y-b=(d-b)/(c-a)(x-a)

And, there's your equation is in point-slope form!

User Sheo
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5.1k points
5 votes

Point-slope form is written as : y - y1 = m(x - x1), where m is the slope and (x1, y1) is the point.

The slope (m) is found by the change in Y over the change in X

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

You can use either given point for x1 and y1 so you would calculate the slope and replace m with the slope, then replace x1 and y1 in the equation with their value.

User Giogre
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5.5k points