Represent the following pair of equations graphically and write the coordinates of points where the lines intersect y-axis :
x + 3y = 6
2x - 3y = 12
Thus, we have the following systems of linear equations
x - y = 2 ...(i)
4x - y = 80 ...(ii)
and x - y = -2 ...(iii)
Case I : From (i), we have
[Considering (i) and (ii)]
x - y = 2
⇒ x = 2 + y ...(iv)
Substituting the value of x in (ii), we get
4x - y - 80
⇒ 4(2 + y) - y = 80
⇒ 8 + 4y - y = 80
⇒ 8 + 3y = 80 ⇒ 3y = 72
⇒ y = 24
Substituting the value ofy in (iv), we get
x = 2 + y = 2 + 24= 26
Hence, Age of A = 26 years
and Age of B = 24 years
Case II : From (iii), we have
[Considering (ii) and (iii)]
x - y = -2 ⇒ x = y - 2 ...(v)
Putting the value of (v) in (ii), we get
4x - y = 80
Substituting the value ofy in (v), we get