Answer:
k = - 3
Explanation:
Given
9kx + 12ky = 63
Since x = - 1 and y = - 1 are solutions of the equation
Substitute x = - 1 and y = - 1 into the equation and solve for k
9k(- 1) + 12k(- 1) = 63, that is
- 9k - 12k = 63
- 21k = 63 ( divide both sides by - 21 )
k = - 3