Question Number 137982 by mey3nipaba last updated on 08/Apr/21
$${y}^{\mathrm{2}} −{x}^{\mathrm{2}} =\mathrm{5}\left({y}−{x}\right)^{\mathrm{2}} .\:{Find}\:{x}:{y} \\ $$
Commented by mey3nipaba last updated on 08/Apr/21
$${please}\:{help} \\ $$
Answered by Dwaipayan Shikari last updated on 08/Apr/21
$$\frac{{y}^{\mathrm{2}} −{x}^{\mathrm{2}} }{\left({y}−{x}\right)^{\mathrm{2}} }=\mathrm{5}\Rightarrow\frac{\left({y}−{x}\right)\left({y}+{x}\right)}{\left({y}−{x}\right)\left({y}−{x}\right)}=\mathrm{5} \\ $$$$\Rightarrow\frac{{y}+{x}}{{y}−{x}}=\mathrm{5}\Rightarrow\frac{{y}+{x}+\left({y}−{x}\right)}{{y}+{x}−\left({y}−{x}\right)}=\frac{\mathrm{5}+\mathrm{1}}{\mathrm{5}−\mathrm{1}}\Rightarrow\frac{{y}}{{x}}=\frac{\mathrm{6}}{\mathrm{4}}\:\: \\ $$$$\Rightarrow\frac{{x}}{{y}}=\frac{\mathrm{2}}{\mathrm{3}} \\ $$
Commented by mey3nipaba last updated on 08/Apr/21
$${thanks}\:{so}\:{much}.\:{i}\:{had}\:{the}\:{answer}\:{but}\:{wanted}\:{to}\:{confirm} \\ $$
Answered by Rasheed.Sindhi last updated on 08/Apr/21
$${An}\:{Alternate}\:{Way} \\ $$$$\frac{{x}}{{y}}={k}\Rightarrow{x}={yk} \\ $$$${y}^{\mathrm{2}} −{x}^{\mathrm{2}} =\mathrm{5}\left({y}−{x}\right)^{\mathrm{2}} \\ $$$$\Rightarrow{y}^{\mathrm{2}} −\left({yk}\right)^{\mathrm{2}} =\mathrm{5}\left({y}−{yk}\right)^{\mathrm{2}} \\ $$$$\:\:\:\:{y}^{\mathrm{2}} \left(\mathrm{1}−{k}^{\mathrm{2}} \right)=\mathrm{5}{y}^{\mathrm{2}} \left(\mathrm{1}−{k}\right)^{\mathrm{2}} \\ $$$$\:\:\:\:{y}^{\mathrm{2}} \left(\mathrm{1}−{k}\right)\left(\mathrm{1}+{k}\right)−\mathrm{5}{y}^{\mathrm{2}} \left(\mathrm{1}−{k}\right)^{\mathrm{2}} =\mathrm{0} \\ $$$$\:\:\:\left(\mathrm{1}−{k}\right)\left(\:{y}^{\mathrm{2}} \left(\mathrm{1}+{k}\right)−\mathrm{5}{y}^{\mathrm{2}} \left(\mathrm{1}−{k}\right)\:\right)=\mathrm{0} \\ $$$$\:\:\:\:{k}=\mathrm{1}\:\mid\:\:{y}^{\mathrm{2}} \left(\mathrm{1}+{k}\right)=\mathrm{5}{y}^{\mathrm{2}} \left(\mathrm{1}−{k}\right)\: \\ $$$$\:\:{x}:{y}=\mathrm{1}:\mathrm{1}\:\:\mid\:\frac{\mathrm{1}+{k}}{\mathrm{1}−{k}}=\frac{\mathrm{5}{y}^{\mathrm{2}} }{{y}^{\mathrm{2}} }=\mathrm{5} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\mid\:\:\:\mathrm{1}+{k}=\mathrm{5}−\mathrm{5}{k} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\mid\:\:\:\:\mathrm{6}{k}=\mathrm{4}\Rightarrow{k}=\mathrm{2}/\mathrm{3} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\mid\:\:\:\:{x}:{y}=\mathrm{2}:\mathrm{3} \\ $$
Answered by nadovic last updated on 08/Apr/21
$${y}^{\mathrm{2}} \:−\:{x}^{\mathrm{2}} \:=\:\mathrm{5}{y}^{\mathrm{2}} \:−\:\mathrm{10}{xy}\:+\:\mathrm{5}{x}^{\mathrm{2}} \\ $$$$\mathrm{6}{x}^{\mathrm{2}} \:−\:\mathrm{10}{xy}\:+\:\mathrm{4}{y}^{\mathrm{2}} \:=\:\mathrm{0} \\ $$$$\mathrm{2}\left(\mathrm{3}{x}^{\mathrm{2}} \:−\:\mathrm{5}{xy}\:+\:\mathrm{2}{y}^{\mathrm{2}} \right)\:=\:\mathrm{0} \\ $$$$\mathrm{2}\left({x}\:−\:{y}\right)\left(\mathrm{3}{x}\:−\:\mathrm{2}{y}\right)\:=\:\mathrm{0} \\ $$$$\frac{{x}}{{y}}\:=\:\mathrm{1}\:\:{or}\:\:\frac{{x}}{{y}}\:=\:\frac{\mathrm{2}}{\mathrm{3}} \\ $$$${x}:{y}\:=\:\mathrm{1}:\mathrm{1}\:\:\:{or}\:\:\:{x}:{y}\:=\:\mathrm{2}:\mathrm{3} \\ $$
Answered by Rasheed.Sindhi last updated on 09/Apr/21
$${y}^{\mathrm{2}} −{x}^{\mathrm{2}} =\mathrm{5}\left({y}−{x}\right)^{\mathrm{2}} .\:{Find}\:{x}:{y} \\ $$$${y}^{\mathrm{2}} \left(\mathrm{1}−\frac{{x}^{\mathrm{2}} }{{y}^{\mathrm{2}} }\right)=\mathrm{5}{y}^{\mathrm{2}} \left(\mathrm{1}−\frac{{x}}{{y}}\right)^{\mathrm{2}} \\ $$$${y}\neq\mathrm{0}\Rightarrow\left(\mathrm{1}−\frac{{x}^{\mathrm{2}} }{{y}^{\mathrm{2}} }\right)=\mathrm{5}\left(\mathrm{1}−\frac{{x}}{{y}}\right)^{\mathrm{2}} \:\: \\ $$$$\frac{{x}}{{y}}={u}\Rightarrow\left(\mathrm{1}−{u}^{\mathrm{2}} \right)=\mathrm{5}\left(\mathrm{1}−{u}\right)^{\mathrm{2}} \\ $$$$\left(\mathrm{1}−{u}\right)\left(\mathrm{1}+{u}\right)−\mathrm{5}\left(\mathrm{1}−{u}\right)^{\mathrm{2}} =\mathrm{0} \\ $$$$\left(\mathrm{1}−{u}\right)\left(\mathrm{1}+{u}−\mathrm{5}+\mathrm{5}{u}\right)=\mathrm{0} \\ $$$$\left(\mathrm{1}−{u}\right)\left(\mathrm{6}{u}−\mathrm{4}\right)=\mathrm{0} \\ $$$${u}=\mathrm{1}\:\mid\:\:{u}=\frac{\mathrm{2}}{\mathrm{3}} \\ $$$${x}:{y}=\mathrm{1}:\mathrm{1}\:\:\mid\:\:{x}:{y}=\mathrm{2}:\mathrm{3} \\ $$
Answered by MJS_new last updated on 09/Apr/21
$$\left({y}−{x}\right)\left({y}+{x}\right)=\mathrm{5}\left({y}−{x}\right)^{\mathrm{2}} \\ $$$$\left(\mathrm{1}\right)\:{y}−{x}=\mathrm{0}\:\:\Rightarrow\:\frac{{x}}{{y}}=\mathrm{1} \\ $$$$\left(\mathrm{2}\right)\:{y}+{x}=\mathrm{5}\left({y}−{x}\right)\:\Rightarrow\:\frac{{x}}{{y}}=\frac{\mathrm{2}}{\mathrm{3}} \\ $$