Basic Algebra/Lines (Linear Functions)/Find the Equation of the Line Using Two Points

Vocabulary Lesson You can find the y intercept(b) of a line by using "point slope" with a pair of cordinates. -Find the slope (y2 - y1) / (x2 - x1) -Use one of the coordinates (points) and use this formula: y-y1=m(x-x1) -Then you end up with y=mx+b Example Problems Find the y-intercept of the following coordinates: (2,1) (3,-7) (1,3) (3,4) (0,2) Example 1: First find the slope m of between the two points: m = (y-y1) / (x-x1) m = (6-2) / (3-5) m = -2 We know that the equation has the form y = mx + b, and we also know that this function passes both of the points, so let's use point #1 to find b: point #1 (2,1) 2 = m(5) + b 2 = (-2)(5) + b b = 12 Alternatively, we can use point #2 and get to the same result. The line equation is: y = -2x + 12 Practice Games Practice Problems