If 3 is a solution of 3x^2 + (k -1) x + 9 = 0, then k =?
If 3 is a solution of 3x^2 + (k -1) x + 9 = 0, then k =?
Explanation
Since 3 is a solution, plug x = 3 into the equation:
3(3)^2 + (k - 1)(3) + 9 = 0
27 + 3k - 3 + 9 = 0
3k + 33 = 0
3k = -33
k = -11