Find the value of k for which the system
kx + 2y = 5
3x + y = 1
has (i) a unique solution, and (ii) no solution.
Solution
The given system of equation may be written as
kx + 2y - 5 = 0
3x + y - 1 = 0
It is of the form
`a_1x + b_1y + c_1 = 0`
`a_2x + b_2y + c_2 = 0`
Where `a_1 = k, b_1 = 2, c_1 = -5`
And `a_2 = 3, b_2 = 1, c_2 = -1`
Where, `a_1 = k, b_1 = 2, c_1 = -5`
And `a_2 = 3, b_2 = 1, c_2 = -1`
1) The given system will have a unique solution, if
`a_1/a_2 != b_1/b_2`
`=> k/3 != 2/1`
`=> k != 6`
So, the given system of equations will have a unique solution, if `k != 6`
2) The given system will have no solution, if
`a_1/a_2 - b_1/b_2 != c_1/c_2`
we have
`b_1/b_2 = 2/1 and c_1/c_2 = (-5)/(-1) = 5/1`
Clearly `b_1/b_2 != c_1/c_2`
So, the given system of equations will have no solution, if
`a_1/a_2 = b_1/b_2`
`=> k/3 = 2/1`
=> k = 6
Hence, the given system of equations will have no solution if k = 6