Given:
the mass of the box is

Gabrielle exert a force in the east direction with a magnitude

Pierre exert a force in the west direction with a magnitude

A friction of force is in west direction

the distance traveled by the box is

Step-by-step explanation:
(A)
first, look at the free body diagram
(B)
from the free body diagram we can the net force is

net force is in east direction.
(C)
from the free body diagram we can write

because

(D)
the net force is in the east direction (means horizontal direction), so the box will accelerate in the horizontal direction towards the east.
(E)
work done is given by

Gabrielle exert a force in east direction and box is also move in the same direction .
work done by Gabrielle is

this work is positive because displacement and force is in the same direction.
(F)
work done by the Pierre is

work done by Pierre is negative because force and displacement are in opposite directions.
(G)
work done by the friction is

This work done is also negative because friction and displacement of the box are in opposite directions to each other.
(H)
total work done is

(I)
net work done by the net force is

this is net work done in the horizontal direction.
(J)
net work done in the vertical direction is zero because net force is zero in the vertical direction and also a box is moved only in the horizontal direction.