Calculating and Showing its Result on GUIDE

I'm quite new on using GUIDE, so please bear with me on this one.

I have this UI layout already, and I know the formula on getting the constants and how to get the x values below the compute button. How can I display the answer on K1, since the operation would be just adding the rows to get the constant? Is the code on showing the answers on X1 - X3 is similar when I start coding on the compute button?