The mathematical explanation is that if f(x) = x + 2 and y (x) = x -2, the relationship is inverse. Also, f(x) = -x and f(x) = 1/x to eliminate a zero value.
Here is the answer for a:
8 * 7 * 6 * 5 * 4 * 3 * 2 * 1
8 = 40320
If you are rounding to the nearest tenth then yes
