2. Aftab tells his daughter, "Seven years ago, I was seven times as old as you were then
Also, three years from now, I shall be three times as old as you will be." Is not the
interesting? Represent this situation algebraically and graphically,
INCERT
Answers
Let Aftab's age right now be x.
Let Aftab's daughter be = y years.
Seven years ago,
Age of Aftab = x - 7
Age of Aftab's daughter = y - 7
Aftab was 7 times as old as Aftab's daughter.
x - 7 = 7(y - 7)
(x - 7) = 7y - 49
x - 7 - 7y + 49 = 0
x - 7y + 42 = 0
Three years later,
Age of Aftab = x + 3
Age of Aftab's daughter = y + 3
Aftab will be three times as Aftab's daughter.
(x + 3) = 3(y + 3)
(x + 3) = 3y + 9
x + 3 - 3y - 9 = 0
x - 3y - 6 = 0
Now, plotting the equation
x - 7y + 42 = 0 (i)
x - 3y -6 = 0 (ii)
Solving (i)
x - 7y + 42 = 0
7y = x + 42
y =
Let x = 0
y =
y =
y = 6
So, x = 0, y = 6 is a solution, i.e., (0,6) is a solution.
Let x = 7
y =
y =
y = 7
So, x = 7, y = 7 is a solution, i.e., (7,7) is a solution.
Solving (ii)
x - 3y - 6 = 0
3y = x - 6
y =
Let x = 0
y =
y =
y = (-2)
So, x = 0, y = -2 is a solution, i.e., (0,-2) is a solution.
Let x = 6
y =
y =
y = 0
So, x = 6, y = 0 is a solution, i.e., (6,0) is a solution.
I have attached the rest of the answer later on......