equation solvers linear mathematical equations

i need solve few mathematical equations application. here's customary instance such an equation:

a + b * c - d / e = a

additional rules:

• b % 10 = 0


• b >= 0


• b <= 100


• each array contingency integer


• ...

i illusory fortitude sets a, b, c, d e.

are there any libraries out there, presumably open source commercial, which i solve such an equation? yes, kind outcome provide?