( #b + #a ) - #c = {#1}
#a : 3 - #c + #b= {#2}
#b + 0.3 * ( #a - #c ) = {#3}
#a + #c : #b = {#4}
( #b + #a ) - #c = #sol1
#a : 3 - #c + #b= #sol2
#b + 0.3 * ( #a - #c ) = #sol3
#a + #c : #b = #sol4