Q: Find the average value of $\displaystyle f(x) = | 7 - x | $ $\displaystyle [4,10] $

My solution: I used $\displaystyle \frac {1}{b-a} \int_{a}^{b} f(x)dx $

So I have $\displaystyle \frac {1}{10-4} \int_{4}^{10} (7 - x) dx $, but the result is 0...

KK