Aftab tells his daughter, "seven yrs ago i was 7 times as old as you were then.

Let the present ages be X and Y, for Aftab and his daughter,

(X - 7) = 7(Y - 7)

X - 7Y = -42  ........(1)

and 

X + 3 = 3(Y +3).

X - 3Y = 6  ............(2)

Solving the two equations for X and Y, we get, X = 42yrs,  Y = 12 yrs.

And algebraically these equations give the situation i.e. equation (1) and (2).

 Graphically the two lines are plotted and their intersection gives, the solution.

Regards,

Team,

TopperLearning.