Folks,

I am struggling with this seemingly simple task of solving for s and t in terms of x and y to ultimately get u in terms of x and y.

(1)

(2)

(3)

My attempt is as follows: From eqn 1 find t, its a quadratic in t

(4)

From (2) find t (5)

Then equate 4 and 5???.... Im actually lost....

The answers are