symbolic linear system solver
[x] = solve(A, b)
matrix (resp. vectors) of character strings
x = solve(A, b) solves A*x = b when A is an upper triangular matrix made of character strings.
x = solve(A, b)
A*x = b
A
A=['1','a';'0','2']; //Upper triangular b=['x';'y']; w=solve(A,b) a=1;x=2;y=5; evstr(w) inv([1,1;0,2])*[2;5]