y in (-oo:+oo)
(3/8)*y+1/2 = (5/8)*y+5/12 // - (5/8)*y+5/12
(3/8)*y-((5/8)*y)+1/2-(5/12) = 0
(3/8)*y+(-5/8)*y+1/2-5/12 = 0
1/12-1/4*y = 0 // - 1/12
-1/4*y = -1/12 // : -1/4
y = -1/12/(-1/4)
y = 1/3
