Split the integral into regions of particular f(x) functions:
int from 0 to 8 of f(x)dx = int from 0 to 4 of (2x-8)dx + int from 4 to 8 of (8-2x)dx
Note that f(x) is continuous at 4.
x2-8x |04 + 8x - x2|48 = 16-32+64-64-(32-16) = -32
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