as a Cartesian vector.
session.masteringengineering.com/problemAsset/2086558/6/Hibbeler14.ch2.p42.jpg
Is this right 4i,3j
If you mean the vector forming the hypotenuse of that little triangle, it is 4i-3j
But F1 is 850 * (4i-3j)/|4i-3j = 850/5 (4i-3j) = 170(4i-3j) = 680i-510j