algorithm - Expression Trees C# for calculating logic equivalence -

recently have programmed recursion function constructing expression tree since expression ((a|b)^c). not problem, problem when time evaluate it, since final tree expression given in next form:

                         ^                        /   \                       |     c                      / \                       b 

and problem raised when time evaluate applying corresponding logic equivalence(in case, distributive law). tried using algorithm evaluating tree if arithmetic expression tree:

evaluate(node) {      if(node has children){           left_val = evaluate(node->left);           right_val = evaluate(node->right);            // find operation symbol node , use           // val = left_val operation right_val            return val;      }      else {           return node_value;      } } 

but didn't succeed @ all, because couldn't values joined in distributive law's form. result, i'd decided better approach , came across approach of expression trees on c# but, i'm not sure if possible; , if it's possible, how can use expression:

a^c  b^c 

i don't know how expression tree works.