The general form of an exponential equation is y = abˣ + k. What is the general form of the following equation?
a. y-4 = 3²ˣ/7
b. y = 9ˣ - 4
c. y = 1/49 x 9ˣ + 4
d. y = 1/7 x 9ˣ + 4
e. y = 7 x 6ˣ + 4