Question Number 204658 by hardmath last updated on 24/Feb/24
$$\mathrm{If}\:\:\:\mathrm{a}\:=\:\sqrt[{\mathrm{3}}]{\mathrm{9}}\:−\:\sqrt[{\mathrm{3}}]{\mathrm{3}}\:+\:\mathrm{1} \\ $$$$\mathrm{Find}\:\:\:\left(\frac{\mathrm{4}\:−\:\mathrm{a}}{\mathrm{a}}\right)^{\mathrm{6}} =\:? \\ $$
Answered by Rasheed.Sindhi last updated on 24/Feb/24
$$\:\mathrm{a}\:=\:\sqrt[{\mathrm{3}}]{\mathrm{9}}\:−\:\sqrt[{\mathrm{3}}]{\mathrm{3}}\:+\:\mathrm{1};\:\left(\frac{\mathrm{4}\:−\:\mathrm{a}}{\mathrm{a}}\right)^{\mathrm{6}} =\:? \\ $$$$\mathrm{let}\:\sqrt[{\mathrm{3}}]{\mathrm{3}}\:=\mathrm{t}\Rightarrow\mathrm{t}^{\mathrm{3}} =\mathrm{3} \\ $$$$\mathrm{a}=\mathrm{t}^{\mathrm{2}} −\mathrm{t}+\mathrm{1} \\ $$$$\left(\frac{\mathrm{4}\:−\:\mathrm{a}}{\mathrm{a}}\right)^{\mathrm{6}} =\left(\frac{\mathrm{4}}{\mathrm{a}}−\mathrm{1}\right)^{\mathrm{6}} =\left(\frac{\mathrm{3}+\mathrm{1}}{\mathrm{a}}−\mathrm{1}\right)^{\mathrm{6}} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:=\left(\frac{\mathrm{t}^{\mathrm{3}} +\mathrm{1}}{\:\mathrm{t}^{\mathrm{2}} −\mathrm{t}+\mathrm{1}}−\mathrm{1}\right)^{\mathrm{6}} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:=\left(\frac{\left(\mathrm{t}+\mathrm{1}\right)\cancel{\left(\:\mathrm{t}^{\mathrm{2}} −\mathrm{t}+\mathrm{1}\right)}}{\cancel{\:\mathrm{t}^{\mathrm{2}} −\mathrm{t}+\mathrm{1}}}−\mathrm{1}\right)^{\mathrm{6}} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:=\left(\mathrm{t}+\mathrm{1}−\mathrm{1}\right)^{\mathrm{6}} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:=\left(\mathrm{t}^{\mathrm{3}} \right)^{\mathrm{2}} =\mathrm{3}^{\mathrm{2}} =\mathrm{9} \\ $$
Answered by A5T last updated on 24/Feb/24
$${Let}\:{p}=\sqrt[{\mathrm{3}}]{\mathrm{3}};\:{a}\left({p}+\mathrm{1}\right)={p}^{\mathrm{3}} +\mathrm{1}=\mathrm{4}\Rightarrow\mathrm{4}−{a}={a}\left({p}+\mathrm{1}\right)−{a} \\ $$$$\Rightarrow\mathrm{4}−{a}={ap}\Rightarrow\left(\frac{\mathrm{4}−{a}}{{a}}\right)^{\mathrm{6}} ={p}^{\mathrm{6}} =\mathrm{3}^{\mathrm{2}} =\mathrm{9} \\ $$