What does it mean to say that's data point has a residual of 0

The correct answer is “the point lies directly on the regression line”

Step-by-step explanation:

When you do a regression analysis, then you get a line of regression that best fits it. The data points usually tend to fall in the regression line, but they do not precisely fall there but around it. A residual is the vertical distance between a data point and the regression line. Every single one of the data points had one residual. If one of this residual is equal to zero, then it means that the regression line truly passes through the point.  

step-by-step explanation:

step 1: solve one of the equations for one of the variables. let's solve the first equation for y:

step 2: substitute that equation into the other equation, and solve for x.

step 3: substitute x = 4 x = 4 x=4 into one of the original equations, and solve for y.