If the domain of the function f(x)=log(0.6)(|2x–5x2–4|) is (–∞,a]∪{b}∪[c,d)∪(e,∞), then the value of a + b + c + d + e is ________. [2026]
(4)
We have, f(x)=log(0.6)(|2x–5x2–4|)
log0.6|2x–5x2–4|≥0
⇒ |2x–5x2–4|≤1
⇒ |2x–5|≤|x2–4|; x≠52, 2, –2
Also, |2x–5|≤|x2–4|
⇒ (2x–5)2≤(x2–4)2
⇒ (x2–4+2x–5)(x2–4–2x+5)≥0
⇒ (x2+2x–9)(x2–2x+1)≥0
⇒ (x2+2x–9)(x–1)2≥0
Since, (x–1)2≥0
⇒ x2+2x–9≥0
⇒ x∈(–∞,–1–10]∪[1}∪(–1+10,∞)
exclude x = 2, 52 (∵ –2 is already excluded)
Hence, x∈(–∞,–1–10]∪[1}∪(–1+10,5/2)∪(5/2,∞)
x∈(–∞,a]∪[b}∪[c,d)∪(e,∞) (Given)
∴ a=–1–10, b=1, c=–1+10, d=5/2, e=5/2
∴ a + b + c + d + c = 4.