SlopeIntercept Form To nd an equation for a line between two points, you need two things. 1. The yintercept of the graph. 2. The slope of the line. lat-ta :211 ' Previously, you learned how to determine the slope between two points. The slope between any two points (:1, yl) and [22, 1,12} is: m. = The procedure for determining a line given two points is the same fivestep process as writing an equation given the slope and a point. First, name the points as being the rst point and the second point, (31:91) (323212) (2! 6) (4a _6] Next, use the coordinates of these points to ll in the formula for calculating the slope of the line. lie1'1 B 12 m. _ 32111 4[2} _ 2 The slope of the line is 2. Next, use the slope of the line and the coordinates of one point to calculate the yintercept of the line. m. = 2 and (26) Next, substitute the values into the slopeintercept form of an equation. y=mz+b l: = 2( l: m Next, perform the multiplication to clear the parenthesis. 6 = 4 + 5 Next, subtract 4 from both sides of the equation to solve for b. 64:44+b Elms Then, substitute the values for m and E) into the slopeintercept form of the equation of a line. y=m+b y=l:lr+l:l