Algebramedium · Past Paper
If the ratio of roots of x^2 + bx + c = 0 is 1:2, then:
A2b^2 = 9c
Bb^2 = 9c
C2b^2 = c
D9b^2 = 2c
✓ Correct Answer: A — 2b^2 = 9c
Roots α, 2α. Sum 3α = -b, Prod 2α^2 = c. α = -b/3. 2(-b/3)^2 = c → 2b^2/9 = c → 2b^2 = 9c.
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