Explanation: The equation of line in slope-intercept form has the following formula: y = mx + c where: m is the slope c is the y-intercept
1- getting the slope: To get the slope, we will need two points from the graph. I will choose the two (0,-80) and (60,-20) slope = (y2-y1) / (x2-x1) = (-20--80) / (60-0) = 1 The equation now is: y = 1x + c y = x + c
2- getting the y-intercept: To get the y-intercept, we will choose a point from the graph, substitute with this point in the equation and solve for c. I will choose point (0,-80) y = x + c -80 = 0 + c c = -80
Based on the above, the equation of the line is: y = x - 80
