We can calculate the slope of this line passing through (4,5) and (8,9) like this: m = (y2 - y1)/(x2 - x1) m = (9 - 5)/(8 - 4) m = 4/4 m = 1 so the slope is 1, and now we can use the equation of one point and the slope to write the line's equation: y - y1 = m(x - x1) y - 5 = 1*(x - 4) y - 5 = x - 4 y = x + 1 that is the equation of the line, its slope is 1 and the y-intercept is 1
