b) ∫ 5 a | x − 5 | d x = ∫ 5 a ( 5 − x ) d x = ( 5 x − x 2 2 ) ∣ ∣ 5 a = 25 2 − ( 5 a − a 2 2 ) .

b) \(\int_a^5 | x - 5|dx = \int_a^5 {(5 - x)} dx = \left. {\left( {5x - \frac{{{x^2}}}{2}} \right)} \right|_a^5 = \frac{{25}}{2} - \left( {5a - \frac{{{a^2}}}{2}} \right)\)

=> Đúng