Explanation:
Starting point is (0,0)
ending point is (-174,38)
There are 4 moves
(20,60)
(bx,-70)
(-20,cx) and (-60,-70)
Take a vector between the starting and ending point
Vector

Vectors for 4 moves are

V is the addition of 4 vectors

Now we replace vector V

component bx is -114
component cy is 118