Moment of a 2-D Force: Solving for P

[arsalan_y]

Homework Statement

A 2-dimensional force of 5[units] in the direction of the line y = 3x (upwards) acts through the
point P = (−1,−2). Find the moment of the force about the origin

Homework Equations

M = Fd

The Attempt at a Solution

i tried putting x = -1 and y = -2 into the y=3x but it doesn't work and i completely don't know how to do it.

 

[arsalan_y]

Homework Statement

A 2-dimensional force of 5[units] in the direction of the line y = 3x (upwards) acts through the
point P = (−1,−2). Find the moment of the force about the origin

Homework Equations

M = Fd

The Attempt at a Solution

i tried putting x = -1 and y = -2 into the y=3x but it doesn't work and i completely don't know how to do it.

i used the quation M= r X F
where OP=r = -i -2j
then i get M = (-i - 2j) X F
i don't know what to do after that to find F