feat: added calcuate function

Author: TatsuyaRyujin

lesson_06/expression/src/expression_calculator.ts

@@ -2,7 +2,10 @@ export class ExpressionCalculator {
   /** Returns a calculation involving a, b, c, d, and e */
   calculate(a: number, b: number, c: number, d: number, e: number): number {
     // Implement your code here to return the correct value.
-    return 0;
+    const base: number = this.add(a, b);
+    const expo: number = c;
+
+    return this.divide(this.pow(base, expo), this.mutiply(d, e));
   }
 
   pow(base: number, exponent: number): number {