Answer:
integrates by parts:
U = x dV = f''
dU = dx V = f'
The integral becomes:
x f' - integral f' dx
= x f' - f
limit as x->4 : 4 * f'(4) - f(4) = 4 * -3 - 7
= -12-7 = -19
limit as x->1 : 1 * f'(1) - f(1) = 1 * 9 - 8 = 1
subtracting: -19-1 = -20
Explanation: