Find the value of k for which each of the following systems of linear equations has an infinite number of solutions:
(k – 3)x + 3y = k,
kx + ky = 12.
Given: (k – 3)x + 3y = k – eq 1
kx + ky = 12 – eq 2
Here,
a1 = (k - 3), b1 = 3, c1 = - k
a2 = k , b2 = k, c2 = - 12
Given that system of equations has infinitely many solution
∴ =
=
=
=
Here,
=
3×( - 12) = - k×(k)
- 36 = - k2
K2 = 36
k = √36
k = ±6
k = 6 and k = - 6 – eq 3
Also,
=
K(k - 3) = 3k
K2 - 3k = 3k
K2 - 6k = 0
K(k - 6) = 0
K = 0 and k = 6 – eq 4
From – eq 3 and – eq 4
k = 6
∴ k = 6