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CGP EDU Academic Team
Published on: August 13, 2026
The equation x 4 – (m – 3)x 2 + m = 0 has
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CHECK THE SOLUTION.
(b, c, d)
x 4 – (m – 3) x 2 + m = 0
if its all roots are real then roots of f(t) = t 2 – (m – 3) t + m = 0 must be non-negative.

i.e. D ≥ 0 ⇒ m ∈ (– ∞ , 1] ∪ [9, ∞ )
α + β > 0 ⇒ m – 3 > 0 ⇒ m > 3
αβ ≥ 0 ⇒ m ≥ 0
So, m ∈ [9, ∞ )
So, for four real and distinct roots m ∈ (9, ∞ ) as D = 0 at m = 9.
both roots of f(t) = 0 are negative for m ∈ (0, 3) & D < 0 for m ∈ (1, 9). Hence no root of given equation for m ∈ (0, 9)
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