Question Number 100954 by bobhans last updated on 29/Jun/20
$$\begin{cases}{\frac{\mathrm{1}}{\mathrm{2}{x}−{y}}\:+\:\sqrt{{y}}\:=\:\mathrm{1}}\\{\frac{\sqrt{{y}}}{\mathrm{2}{x}−{y}}\:=\:−\mathrm{6}}\end{cases} \\ $$
Commented by Dwaipayan Shikari last updated on 29/Jun/20
$$\:\:\:\:\:\:\:\:\:\frac{−\mathrm{6}}{\:\sqrt{{y}}}=\frac{\mathrm{1}}{\mathrm{2}{x}−{y}}\:\:\:\:\:\:\rightarrow\left(\mathrm{1}\right) \\ $$$$ \\ $$$$\:\:\:\:\:\:\:\:\frac{−\mathrm{6}}{\:\sqrt{{y}}}+\sqrt{{y}}=\mathrm{1}\:\:\:\:\Rightarrow{t}^{\mathrm{2}} −{t}−\mathrm{6}=\mathrm{0}\Rightarrow{t}=\:\:\mathrm{3}\:\:{or}\:\:−\mathrm{2}\:\:\:\:\:\left\{{suppose}\:\sqrt{{y}}={t}\right\} \\ $$$$\frac{−\mathrm{6}}{\mathrm{3}}=\frac{\mathrm{1}}{\mathrm{2}{x}−\mathrm{9}\:}\Rightarrow−\mathrm{4}{x}+\mathrm{18}=\mathrm{1}\:\:\:\Rightarrow{x}=\frac{\mathrm{17}}{\mathrm{4}}\:\: \\ $$$$\begin{cases}{{x}=\frac{\mathrm{17}}{\mathrm{4}}}\\{{y}=\mathrm{9}}\end{cases} \\ $$$$ \\ $$$$ \\ $$
Answered by ajfour last updated on 29/Jun/20
$${s}=\frac{\mathrm{1}}{\mathrm{2}{x}−{y}}\:\:,\:\:{t}=\sqrt{{y}} \\ $$$${s}+{t}=\mathrm{1}\:\:,\:\:\:{st}=−\mathrm{6}\:\:\:\:\Rightarrow\:\:{t}>\mathrm{0}\:,\:\:{s}<\mathrm{0} \\ $$$${s},\:{t}\:=\:\frac{\mathrm{1}}{\mathrm{2}}\pm\sqrt{\frac{\mathrm{1}}{\mathrm{4}}+\mathrm{6}}\: \\ $$$${t}=\frac{\mathrm{1}}{\mathrm{2}}+\frac{\mathrm{5}}{\mathrm{2}}\:=\:\mathrm{3}\:\:\:,\:\:{s}=\:−\mathrm{2} \\ $$$$\Rightarrow\:\:{y}=\:{t}^{\mathrm{2}} \:=\:\mathrm{9}\:,\: \\ $$$${s}=\frac{\mathrm{1}}{\mathrm{2}{x}−{y}}=\:\frac{\mathrm{1}}{\mathrm{2}{x}−\mathrm{9}}\:=\:−\mathrm{2} \\ $$$$\Rightarrow\:\:\mathrm{2}{x}=\mathrm{9}−\frac{\mathrm{1}}{\mathrm{2}}\:\:\Rightarrow\:\:\:{x}=\frac{\mathrm{17}}{\mathrm{4}}\:. \\ $$
Answered by john santu last updated on 29/Jun/20
$$\Rightarrow\frac{\mathrm{1}}{\mathrm{2}{x}−{y}\:}\:=\:−\frac{\mathrm{6}}{\:\sqrt{{y}}}\:\left(\mathrm{1}\right) \\ $$$$\Rightarrow−\frac{\mathrm{6}}{\:\sqrt{{y}}\:}\:+\sqrt{{y}}\:=\:\mathrm{1}\:;\:\left(\sqrt{{y}}\right)^{\mathrm{2}} −\sqrt{{y}}\:−\mathrm{6}\:=\mathrm{0} \\ $$$$\left(\sqrt{{y}}\:−\mathrm{3}\right)\left(\sqrt{{y}}\:+\mathrm{2}\:\right)\:=\:\mathrm{0}\:;\:\sqrt{{y}}\:=\:\mathrm{3} \\ $$$${y}=\:\mathrm{9}\:\Rightarrow\frac{\mathrm{1}}{\mathrm{2}{x}−\mathrm{9}}\:=\:−\mathrm{2}\:;\:\mathrm{2}{x}−\mathrm{9}\:=\:−\frac{\mathrm{1}}{\mathrm{2}} \\ $$$$\mathrm{2}{x}\:=\:\frac{\mathrm{17}}{\mathrm{2}}\:,\:{x}\:=\:\frac{\mathrm{17}}{\mathrm{4}} \\ $$