Linear Regression model visualization
If there are 20 independent variables and 1 dependent variable, a linear regression model can be viewed as a 20-dimensional hyperplane in 21-dimensional space. The hyperplane is not "vertical" with respect to any independent variable. So if you pick a value for each of the 20 independent variables and draw a vertical line at the point consisting of those values, it will cross the hyperplane once at the height that the model outputs when you plug in the values of the independent variables.