Line is tangent to the graph of at point , with coordinates where . Point has coordinates . Line crosses the x-axis at the point , with coordinates .

a) Find the value of when .

b) For all , find in terms of .

c) Suppose that is increasing at the constant rate of 7 units per second. When , what is the rate of change of with respect to time?

d) Suppose that is increasing at the constant rate of 7 units per second. When , what is the rate of change of the area of triangle with respect to time? Determine whether the area is increasing or decreasing at this instant.

Please help on any and/or all of these that you can, I'd very much appreciate it! And for those of you who might ask me to show my process of thought, I honestly don't even know where to start; I'm so confused.