Finding the equation for a multiple and nonlinear regression model? Regarding nonlinear and multivariable regression, I am using R or Matlab. In the case where I have a regression with just two variables, I simply draw the graph Y with respect to X and look for the equation of the model that corresponds the most to the distribution of the point cloud.

However, in the case where Y is connected with several independent variables (in my case 12 variables $X_1, X_2,...,X_{12}$). How will I be able to define the equation of the regression model?
This question clearly is the basics of linear regression. 

If you are looking for a way to implement linear regression in R, use the lm method.

fit &lt;- lm(y~X1+X2, data = datasetname)

summary(fit) 


This should give the coefficients and the p value for each variable.