Consider that the equation of a striaght line passing through two points is given by,
[tex]y-y_1=\frac{y_2-y_1}{x_2-x_1}\times(x-x_1)[/tex]
Consider that the best fit line of the scatter plot passes through (20,50) and (30,40).
So the equation of the best fit line is given by,
[tex]\begin{gathered} y-50=\frac{40-50}{30-20}\times(x-20) \\ y-50=-1(x-20) \\ y-50=-x+20 \\ y=70-x \end{gathered}[/tex]
Here in this question, 'y' represents the number of text messages while 'x' gives the age of the person
