Yes the answer is -2. The value of integral between 0 and 1 is negative, as f(x) is under the x axis.
The value of integral from 1 to 3 is positive as f(x) is above the x axis.
Whenever the integral is positive its value is equal to the area.
Whenever the integral is negative its value is equal to minus the value of area.
As the area from 1 to 3 is 5, the rest of the area is the one between x=0 and x=1 and is 2.
Hope it helps.
Reza Bokat,
Cambridge Coaching
www.cambridgecoaching.com.au