alleryIf one root of x^2 - 6x + k = 0 is 2, then k equals
A6
B4
C8
D12
Answer & Solution
Correct answer: C. 8
1. Substitute x = 2 in the equation.
2. (2)^2 - 6(2) + k = 0.
3. 4 - 12 + k = 0, so k = 8.
4. Therefore k = 8.
_Source: Selina Concise Mathematics Class 10, Ch 5 Quadratic Equations (Mistral OCR'd PDF), section on root substitution_
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