code: function(symbol, solve_for) {
          var sols = [];
          //see if we can solve the factors
          var factors = core.Algebra.Factor.factor(symbol);
          if(factors.group === CB) {
              factors.each(function(x) {
                  x = Symbol.unwrapPARENS(x);
                  sols = sols.concat(solve(x, solve_for));
              });
          }
          return sols;
      }
docs: solve by divide and conquer