Algebrahard · Past Paper
Find k if one root of x^2 - (k+1)x + 12 = 0 is 3.
A6
B7
C5
D4
✓ Correct Answer: A — 6
Substitute x=3: 9 - 3(k+1) + 12 = 0 → 21 - 3k - 3 = 0 → 18 = 3k → k = 6.
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✓ Correct Answer: A — 6
Substitute x=3: 9 - 3(k+1) + 12 = 0 → 21 - 3k - 3 = 0 → 18 = 3k → k = 6.
Share this question