Solution
Step 1:
The magnitude of a vector is the length of the vector itself.
Given a bi-dimensional vector, the magnitude of the vector is given by:

Step 2:
where
Vx is the x-component of the vector
Vy is the y-component of the vector
Step 3:
The vector in the problem is ( 7 , -5 )
Where

Step 4:

Final answer
