The gradient descent equation itself is generally the same form; we just have to repeat it for our 'n' features:

[Machine Learning] Gradient Descent For Multiple Variables_[Machine Learning]

In other words:

[Machine Learning] Gradient Descent For Multiple Variables_[Machine Learning]_02

The following image compares gradient descent with one variable to gradient descent with multiple variables:

[Machine Learning] Gradient Descent For Multiple Variables_[Machine Learning]_03