Here is an example of multiple linear regression using R:

library(MASS) #  MASS package is a very large collection of data sets and functions
library(ISLR) # ISLR package includes the data sets associated with this book
lm.fit=lm(medv∼lstat+age,data=Boston)# medv as a response, lstat and age as two predictors
summary(lm.fit) # gives us p-values and standard errors for the coefficients, as well as the R2 statistic and F-statistic for the model

#The syntax lm(y∼x1+x2+x3) is used to fit a model with three predictors, #x1, x2, andx3. The summary() function now outputs the regression #coefficients for all the predictors. 

#We can also make a regression using all predictors with the following code:
lm.fit=lm(medv∼.,data=Boston)