Hi Shirley, to answer this question, start by finding the slope represented by the two points.

Slope = (y_{2} - y_{1}) / (x_{2} - x_{1})

It does not matter which point is used for (x_{1}, y_{1}) or (x_{2},_{ }y_{2})

Let (5, 2) be the (x_{2}, y_{2}) point and (4, 1) be the (x_{1}, y_{1})

Slope = (2 - 1) / (5 - 4)

Slope = 1 / 1 or 1

Next, find the point-slope form of the line using the slope, m, and one of the two given points and again, it does not matter which point is selected.

y - y_{1} = m * (x - x_{1})

m = 1

y_{1} = 2

x_{1} = 5

Substituting:

y - 2 = 1 * (x - 5)

Clear parenthesis:

y - 2 = x - 5

You now have the point slope format of the line.

Add 2 to both sides:

y = x - 3

You now have the slope-intercept form of the line.

questions?