counterclockwise moment

Problem 260
The effect of a certain non-concurrent force system is defined by the following data: ΣF_x = +90 kN, ΣF_y = -60 kN, and ΣM_O = 360 kN·m counterclockwise. Determine the point at which the resultant intersects the x-axis.
 

Problem 251
A vertical force P at A and another vertical force F at B in Fig. P-251 produce a resultant of 100 lb down at D and a counterclockwise couple C of 200 lb·ft. Find the magnitude and direction of forces P and F.
 

Problem 233
In Fig. P-231, a force P intersects the X axis at 4 ft to the right of O. If its moment about A is 170 ft·lb counterclockwise and its moment about B is 40 ft·lb clockwise, determine its y intercept.
 

Problem 232
In Fig. P-231, the moment of a certain force F is 180 ft·lb clockwise about O and 90 ft·lb counterclockwise about B. If its moment about A is zero, determine the force.