simplify solve output

[mschuene]

(solve '[x y](ex %28= y %28* x 4/3%29%29) ;; y = 4/3 x
(ex (= y (+ 1 -1 (* x 4/3))))) ;; y = 4/3 x
returns #{{x (* (- _0) -3/4), y _0}} , which is correct but can be simplified further to

{{x (* _0 3/4), y _0}}

[Vaguery]

Well, technically it can be simplified to #{{x _0, y (* 4/3 _0)}} (if I understand the notation correctly).