A box on the floor with a mass of 2 kg is under the effect of forces F1, F2 and F3 as it shows below. If the box moved a distance of 3 m. Calculate the work done on the box? HELP please.

$F 2$ is irrelevant because it is at right angles to the direction of motion. Vector addition of $F 1$ and $F 3$ yields a net force of $10$ $N$ to the right.
$W = F d = 10 \times 3 = 30$ $J$
The work done is the product of the net force acting and the distance travelled (in the direction of the net force), $W = F d$.