8. (9 points) Let l be a line in the x-y plane. If I is a vertical line, its equation is x = a for some real number a. Suppose l is not a vertical line and its slope is m. Then the equation of lis y = mx +b, where b is the y-intercept. If I passes through the point (xo, Yo,), the equation of I can be written as y-yo = m(x - xo). If (x1, Y) and (x2, Y2) are two points in the x-y plane and x1 + x2, the slope of the line passing through these points is m = (y2 - Y) / (x2 - x). Write a program that prompts the user to enter two points in the x-y plane. The program outputs the equation of the line and uses if statements to determine and output whether the line is vertical, horizontal, increasing, or decreasing. If I is a nonvertical line, output its equation in the form y = mx +b