Find all solutions to the following nonlinear system in four variables (u+3u) (a:+y) = 1 (u+3u) + 2(a:+y) = 4 6(u u)2 2(32 y)2 = 6 2(u v? + (x y)? = 1, by solving graphically several suitable lin systems with 2 variables and 2 constraints (ale, describe these systems, draw the lines corresponding to the equations in the plane, and pinpoint their intersection on the gures). [Hint Is there an easy way to nd the value of u+3u and Ic+y? What about the value of (uu)2 and (:c y)2 .9]