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log-2-8x-log-3-27x-x-2-x-0-




Question Number 90434 by john santu last updated on 23/Apr/20
((log_2 (8x).log_3 (27x))/(x^2 −∣x∣)) ≤ 0
$$\frac{\mathrm{log}_{\mathrm{2}} \left(\mathrm{8}{x}\right).\mathrm{log}_{\mathrm{3}} \left(\mathrm{27}{x}\right)}{{x}^{\mathrm{2}} −\mid{x}\mid}\:\leqslant\:\mathrm{0}\: \\ $$
Commented by jagoll last updated on 28/Apr/20
how (1/8) < (1/(27)) ?
$${how}\:\frac{\mathrm{1}}{\mathrm{8}}\:<\:\frac{\mathrm{1}}{\mathrm{27}}\:?\: \\ $$
Commented by john santu last updated on 23/Apr/20
(1) x>0  ⇒ (((8x−1)(27x−1))/(x^2 −x)) ≤ 0  (((x−(1/8))(x−(1/(27))))/(x(x−1))) ≤ 0  ⇒ 0 < x ≤ (1/(27)) ∨ (1/8) ≤ x < 1
$$\left(\mathrm{1}\right)\:{x}>\mathrm{0} \\ $$$$\Rightarrow\:\frac{\left(\mathrm{8}{x}−\mathrm{1}\right)\left(\mathrm{27}{x}−\mathrm{1}\right)}{{x}^{\mathrm{2}} −{x}}\:\leqslant\:\mathrm{0} \\ $$$$\frac{\left({x}−\frac{\mathrm{1}}{\mathrm{8}}\right)\left({x}−\frac{\mathrm{1}}{\mathrm{27}}\right)}{{x}\left({x}−\mathrm{1}\right)}\:\leqslant\:\mathrm{0} \\ $$$$\Rightarrow\:\mathrm{0}\:<\:{x}\:\leqslant\:\frac{\mathrm{1}}{\mathrm{27}}\:\vee\:\frac{\mathrm{1}}{\mathrm{8}}\:\leqslant\:{x}\:<\:\mathrm{1} \\ $$
Commented by mahdi last updated on 24/Apr/20
(1/8)≤x≤(1/(27)) ∪ 1≤x
$$\frac{\mathrm{1}}{\mathrm{8}}\leqslant\mathrm{x}\leqslant\frac{\mathrm{1}}{\mathrm{27}}\:\cup\:\mathrm{1}\leqslant\mathrm{x} \\ $$

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