diff --git a/ex1/computeCostMulti.m b/ex1/computeCostMulti.m
index 5f59913..22e462b 100644
--- a/ex1/computeCostMulti.m
+++ b/ex1/computeCostMulti.m
@@ -13,7 +13,11 @@ J = 0;
 % Instructions: Compute the cost of a particular choice of theta
 %               You should set J to the cost.
 
+predictions = X * theta;
+errors = predictions - y;
+squared_errors = errors .^ 2;
 
+J = 1/(2*m) * sum(squared_errors);
 
 % =========================================================================