Can somebody solve this problem for me?

[086]

http://postimg.org/image/r6onkhvg7/

[az_lender]

I'll call the unknown forces FB, FC, and FD.
[Edit: sorry, had to insert some minus signs!]

FB_z + FC_z + FD_z = 1200N
FB*[h/sqrt(h^2+m^2)] + FC*[h/sqrt(h^2+g^2)] +
+ FD*[h/sqrt(e^2+f^2+h^2)] = 1200 N
Call that Equation 1.

FB_x + FC_x + FD_x = 0
FB*[m/sqrt(h^2+m^2)] + FC*0 +
+ FD*[-e/sqrt(e^2+f^2+h^2)] = 0
Call that Equation 2.

FB_y + FC_y + FD_y = 0
FB*0 + FC*[g/sqrt(g^2+h^2) +
+ FD*[-f/sqrt(e^2+f^2+h^2)] = 0
Call that Equation 3.

Substitute the given numbers e,f,g,h,m
into these three equations, and then use
high-school methods to get a simultaneous solution
for the 3 unknowns (FB, FC, FC).