How do you find torque for a particle at a specific point using vector products?

[Sheneron]

[SOLVED] Vector products and torque

Homework Statement

A particle is located at the vector position r = (i + 3j) m, and the force acting on it is F = (1i + 7j) N.
(a) What is the torque about the origin?
(b) What is the torque about the point having coordinates (0, 4) m?

The Attempt at a Solution

I got the answer for the first part, but I am confused about part b. At first I thought I was supposed to just switch (i +3j) with (0,4) but that is not right. So then I thought that maybe I was supposed to do this:
(1,3) - (0,4) = new vector, and the coordinates for the new vector to find the torque which would be equal to 8 nm. Is that how I am supposed to do it?

 

[Shooting Star]

Quite correct.

 

[Sheneron]

I thank ye