Question

2x+3y=7
(K-1)x+(k+2)y=3k
Find the value of k for which this pair of equation has only one solution

Answer 1

use the formula: of cross multiplication
2/k-1=3/k+2=-7/-3k
2×(k+2)=3×(k-1)
2k+4=3k-3
2k-3k=-3-4
-k=-7
k=7