Use geometry software to investigate the form y = ax + b of a linear function.
a. On the same coordinate plane, graph the lines y = 0.5x + 4, y = x + 4, y = 2x + 4, y = 5x + 4, y = - 3x + 4, and y = - 0.25x + 4. Describe the graphs of the family of lines y = ax + 4 as a takes on different values.
b. On the same coordinate plane, graph the lines y = 2x - 7, y = 2x - 2, y = 2x, y = 2x + 3, and y = 2x + 8. Describe the graphs of the family of lines y = 2x + b as b takes on different values.