9514 1404 393
Answer:
-7
Step-by-step explanation:
An even function is symmetrical about the y-axis. That is, f(x) = f(-x). Any portion of the curve with a positive slope on the right of the y-axis will be reflected as curve with a negative slope on the left side of the y-axis.
f'(-11) = -f'(11) = -7
