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x-2-5-9-y-x-2-5-9-y-y-2-4-9-x-y-2-4-9-x-Find-x-y-




Question Number 185127 by Shrinava last updated on 17/Jan/23
 { (((√(x^2  − (5/9) + (√(y + x^2  − (5/9))))) = y)),(((√(y^2  − (4/9) + (√(x + y^2  − (4/9))))) = x)) :}  Find:   x , y = ?
$$\begin{cases}{\sqrt{\mathrm{x}^{\mathrm{2}} \:−\:\frac{\mathrm{5}}{\mathrm{9}}\:+\:\sqrt{\mathrm{y}\:+\:\mathrm{x}^{\mathrm{2}} \:−\:\frac{\mathrm{5}}{\mathrm{9}}}}\:=\:\mathrm{y}}\\{\sqrt{\mathrm{y}^{\mathrm{2}} \:−\:\frac{\mathrm{4}}{\mathrm{9}}\:+\:\sqrt{\mathrm{x}\:+\:\mathrm{y}^{\mathrm{2}} \:−\:\frac{\mathrm{4}}{\mathrm{9}}}}\:=\:\mathrm{x}}\end{cases} \\ $$$$\mathrm{Find}:\:\:\:\mathrm{x}\:,\:\mathrm{y}\:=\:? \\ $$
Commented by Frix last updated on 17/Jan/23
x=(5/9)∧y=(4/9)
$${x}=\frac{\mathrm{5}}{\mathrm{9}}\wedge{y}=\frac{\mathrm{4}}{\mathrm{9}} \\ $$
Commented by Shrinava last updated on 17/Jan/23
solution please dear ser
$$\mathrm{solution}\:\mathrm{please}\:\mathrm{dear}\:\mathrm{ser} \\ $$
Commented by Frix last updated on 17/Jan/23
The easiest way is to set y=px  Squaring and transforming both equations  two times and then subtracting leads to  a quadratic equation which is easy to solve  for p or x.  Then we get 4 solutions which we must  check ⇒ only 1 solution is valid.
$$\mathrm{The}\:\mathrm{easiest}\:\mathrm{way}\:\mathrm{is}\:\mathrm{to}\:\mathrm{set}\:{y}={px} \\ $$$$\mathrm{Squaring}\:\mathrm{and}\:\mathrm{transforming}\:\mathrm{both}\:\mathrm{equations} \\ $$$$\mathrm{two}\:\mathrm{times}\:\mathrm{and}\:\mathrm{then}\:\mathrm{subtracting}\:\mathrm{leads}\:\mathrm{to} \\ $$$$\mathrm{a}\:\mathrm{quadratic}\:\mathrm{equation}\:\mathrm{which}\:\mathrm{is}\:\mathrm{easy}\:\mathrm{to}\:\mathrm{solve} \\ $$$$\mathrm{for}\:{p}\:\mathrm{or}\:{x}. \\ $$$$\mathrm{Then}\:\mathrm{we}\:\mathrm{get}\:\mathrm{4}\:\mathrm{solutions}\:\mathrm{which}\:\mathrm{we}\:\mathrm{must} \\ $$$$\mathrm{check}\:\Rightarrow\:\mathrm{only}\:\mathrm{1}\:\mathrm{solution}\:\mathrm{is}\:\mathrm{valid}. \\ $$

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