Posted by True on .
For what value of k does the system below not have a unique solution?
1x + 7y + 2z = 6
2x + 1y + kz = 11
3x  6y  2z = 25
A.5
B.0
C.2
D.8

mathematics please help! 
Damon,
determinant = 2+21k2466k+28
If the determinant is zero, we can not solve for the variables
0 +15 k = 0
k = 0