Writing Linear Equations Using Charts

Students learn to write the equation of a line in slope-intercept form using a table of ordered pairs. The first step is to determine if the ordered pairs in the table lie on a line, so that slope-intercept form, or y = mx + b form, can be used to write the equation of the line. If the rate of change is constant, then the ordered pairs lie on a line. Next, to find the slope of the line, remember that the rate of change is equal to the slope. To find the y-intercept, substitute the slope in for m in the formula y = mx + b, and substitute a given ordered pair in the table for x and y in the formula, then solve for b. Finally, substitute the values for m and b into the formula y = mx + b to write the equation of the line.