If we use only X and y, we can write y = mx + c equation for linear regression. But now I have another 2 variables. So now I have 4 variables. Let's think "x, y, z, w" as my 4 variables. How can I write the equation? If we use linear regression, we can use y = mx + c formula. but it will only represent x and y. but I want to incorporate all x, y, z, and w all together in one formula.
What will be the equation?