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Category: Algebra

Let-a-b-c-gt-0-and-c-2-ab-bc-ca-3-Prove-that-a-3-b-3-2c-3-a-3-b-3-c-3-3-a-2-b-2-2c-2-a-2-b-2-c-2-

Question Number 78340 by loveineq. last updated on 16/Jan/20 $$\mathrm{Let}\:\:{a},{b},{c}\:>\:\mathrm{0}\:\:\mathrm{and}\:\:{c}^{\mathrm{2}} \:=\:\frac{{ab}+{bc}+{ca}}{\mathrm{3}}\:.\:\mathrm{Prove}\:\mathrm{that} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\frac{{a}^{\mathrm{3}} +{b}^{\mathrm{3}} −\mathrm{2}{c}^{\mathrm{3}} }{{a}^{\mathrm{3}} +{b}^{\mathrm{3}} +{c}^{\mathrm{3}} }\:\leqslant\:\mathrm{3}\left(\frac{{a}^{\mathrm{2}} +{b}^{\mathrm{2}} −\mathrm{2}{c}^{\mathrm{2}} }{{a}^{\mathrm{2}} +{b}^{\mathrm{2}} +{c}^{\mathrm{2}} }\right)…

The-sum-of-age-of-Hamadou-his-wife-and-theirs-son-is-100-n-years-ago-the-wife-had-the-quadruple-of-his-son-s-age-and-Hamadou-was-6-time-older-than-his-son-Determine-theirs-ages-i-want-that-yo

Question Number 78306 by mathocean1 last updated on 15/Jan/20 $$\mathrm{The}\:\mathrm{sum}\:\mathrm{of}\:\mathrm{age}\:\mathrm{of}\:\mathrm{Hamadou}\:\:\: \\ $$$$\mathrm{his}\:\mathrm{wife}\:\mathrm{and}\:\mathrm{theirs}\:\mathrm{son}\:\mathrm{is}\:\mathrm{100}. \\ $$$$\mathrm{n}\:\mathrm{years}\:\mathrm{ago}\:\mathrm{the}\:\mathrm{wife}\:\mathrm{had}\:\mathrm{the}\: \\ $$$$\mathrm{quadruple}\:\mathrm{of}\:\mathrm{his}\:\mathrm{son}'\mathrm{s}\:\mathrm{age}\:\mathrm{and}\: \\ $$$$\mathrm{Hamadou}\:\mathrm{was}\:\mathrm{6}\:\mathrm{time}\:\mathrm{older}\:\mathrm{than} \\ $$$$\mathrm{his}\:\mathrm{son}. \\ $$$$\mathrm{Determine}\:\mathrm{theirs}\:\mathrm{ages}. \\ $$$$ \\…

Solve-simultaneously-2x-y-z-8-equation-i-x-2-y-2-2z-2-14-equation-ii-3x-3-4y-3-z-3-195-equation-iii-

Question Number 12763 by tawa last updated on 30/Apr/17 $$\mathrm{Solve}\:\mathrm{simultaneously} \\ $$$$\mathrm{2x}\:+\:\mathrm{y}\:−\:\mathrm{z}\:=\:\mathrm{8}\:\:\:\:\:\:\:\:………..\:\mathrm{equation}\:\left(\mathrm{i}\right) \\ $$$$\mathrm{x}^{\mathrm{2}} \:−\:\mathrm{y}^{\mathrm{2}} \:+\:\mathrm{2z}^{\mathrm{2}} \:=\:\mathrm{14}\:\:\:\:\:\:\:……….\:\mathrm{equation}\:\left(\mathrm{ii}\right) \\ $$$$\mathrm{3x}^{\mathrm{3}} \:+\:\mathrm{4y}^{\mathrm{3}} \:+\:\mathrm{z}^{\mathrm{3}} \:=\:\mathrm{195}\:\:\:\:\:\:\:\:\:………..\:\mathrm{equation}\:\left(\mathrm{iii}\right) \\ $$ Terms…

x-4-ax-2-bx-c-0-let-x-t-s-t-4-as-2-t-2-bs-3-t-cs-4-0-let-t-p-h-p-4-4hp-3-6h-2-p-2-4h-3-p-h-4-as-2-p-2-2hp-h-2-bs-3-p-h-cs-4-0-p-4-4hp-3-6h-2-as-2-p-2-4h-3-2ahs-2-

Question Number 143822 by ajfour last updated on 18/Jun/21 $$\:{x}^{\mathrm{4}} +{ax}^{\mathrm{2}} +{bx}+{c}=\mathrm{0} \\ $$$${let}\:\:{x}=\frac{{t}}{{s}} \\ $$$$\Rightarrow\:{t}^{\mathrm{4}} +{as}^{\mathrm{2}} {t}^{\mathrm{2}} +{bs}^{\mathrm{3}} {t}+{cs}^{\mathrm{4}} =\mathrm{0} \\ $$$${let}\:{t}={p}+{h}\:\:\Rightarrow \\ $$$${p}^{\mathrm{4}}…

a-b-c-R-find-all-f-R-R-such-that-f-a-f-bc-9-f-ab-5f-ac-

Question Number 143814 by mathdanisur last updated on 18/Jun/21 $$\forall{a};{b};{c}\in\mathbb{R}\:,\:{find}\:{all}\:{f}:\mathbb{R}\rightarrow\mathbb{R}\:,\:{such}\:{that} \\ $$$${f}\left({a}\right){f}\left({bc}\right)+\mathrm{9}\leqslant{f}\left({ab}\right)+\mathrm{5}{f}\left({ac}\right) \\ $$ Answered by Olaf_Thorendsen last updated on 18/Jun/21 $${f}\left({a}\right){f}\left({bc}\right)+\mathrm{9}\:\leqslant\:{f}\left({ab}\right)+\mathrm{5}{f}\left({ac}\right) \\ $$$$ \\…