Answer
$(-4.021Nx+0.965Ny)$
Work Step by Step
Along x-axis,
$F_{1}cos37^{\circ}+F_{2}-F_{3}sin45^{\circ}=4.021N$
Along y-axis,
$F_{1}sin37^{\circ}-F_{3}cos45^{\circ}-F_{4}=-0.965N$
Total force acting on the body =
$4.021Nx-0.965Ny$
For constant speed, sum of forces should be zero.
So, the force to act upon the body must be $(-4.021Nx+0.965Ny)$