Given the information in the table, we can calculate the slope of the line using the equation:
Where x₁ and x₂ are the months number 3 and 8, respectively. y₁ and y₂ are the lengths of the hair in those months. Then:
Now, using the point-slope form of the equation of the line:
To calculate if their hair length would ever be equal, we use the equations above:
They will be equal after 33 months.