solve graphically the following equation x-y=3;2x+3y=36
Answers
Answer:
Let the present age of Aftab = x
and present age of his daughter is represented as = y
Seven years ago,
Aftab’s age = x – 7
Age of Aftab’s daughter = y – 7
According to the question,
(x – 7) = 7 (y – 7 )
=> x – 7 = 7 y – 49
=> x – 7y = – 49 + 7
=> x – 7y = – 42 … (i)
=> x = 7y – 42
=> Putting y = 5, 6 and 7, we get
=> x = 7 * 5 – 42 = 35 – 42 = – 7
=> x = 7 * 6 – 42 = 42 – 42 = 0
=> x = 7 * 7 – 42 = 49 – 42 = 7
x
-7
0
7
y
5
6
7
Three years from now,
Aftab’s age = x + 3
Age of Aftab’s daughter = y + 3
According to the question,
(x + 3) = 3 (y + 3)
=> x + 3 = 3y + 9
=> x – 3y = 9 – 3
=> x – 3y = 6 … (ii)
=> x = 3y + 6
=> Putting, y = – 2, –1 and 0, we get
=> x = 3 * (-2) + 6 = – 6 + 6 =0
=> x = 3 * (-1) + 6 = – 3 + 6 = 3
=> x = 3 * 0 + 6 = 0 + 6 = 6
x
0
3
6
y
-2
-1
0
From equation (i) and (ii)
x – 7y = – 42 … (i)
x – 3y = 6 … (ii)
Graphical representation is given as above.