For part a:
In an even function, the function is symmetrical over the y axis. The left half exactly reflects the right half. Imagine y = x^2.
Since the curves of the right and left side of the function are the same, they have the same derivative values. However, derivatives are found when x is increasing, and on the left side of the function, it is decreasing, but at the same speed.
So, f’(-10) would be -6
B: I’m not exactly sure but my gut is telling me 0.