(3^(x) - 9)√x²-2x-8 ≤0.
(3^(x)-9)sqrt(x^(2)-2x-8) ≤ 0, {3^(x)-9 ≤ 0, {x^(2)-2x-8 ≥ 0; {3^(x) ≤ 3^(2), {(x-4)(x+2) ≥ 0; {x ≤ 2, {x ≤ -2 или x ≥ 4; x ≤ -2, x ∈ (- ∞ ;-2].