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Question-99807




Question Number 99807 by PengagumRahasiamu last updated on 23/Jun/20
Answered by ajfour last updated on 23/Jun/20
x=54, y=24, z=6  x+y+z=84.
$${x}=\mathrm{54},\:{y}=\mathrm{24},\:{z}=\mathrm{6} \\ $$$${x}+{y}+{z}=\mathrm{84}. \\ $$$$ \\ $$
Commented by PengagumRahasiamu last updated on 23/Jun/20
How to solve this?
Answered by ajfour last updated on 24/Jun/20
x−y+(√z)((√x)−(√y))=42−6  and  y−z+(√x)((√y)−(√z))=6+30  ⇒    ((√x)−(√y))((√x)+(√y)+(√z))=36   ..(i)   ((√y)−(√z))((√x)+(√y)+(√z))=36    ..(ii)  ⇒   (√x)−(√y) = (√y)−(√z)  or   (√x)+(√z)=2(√y)  Adding (i),(ii)    ((√x)−(√z))(3(√y))=36+36  ⇒   ((√x)−(√z))((√x)+(√z))=((72×2)/3)  ⇒     x−z = 48    ....(I)     Now    y−(√(xz)) = 6  ⇒      ((((√x)+(√z))/2))^2 −(√(xz)) = 6  ⇒     ((√x)−(√z))^2 =24             (√x) −(√z) = 2(√6)  and using   z=x−48    [see (I)]       (√x)−(√(x−48)) = 2(√6)     .....(iv)       Also   ((48)/( (√x)+(√(x−48)))) = 2(√6)  ⇒   (√x)+(√(x−48))  = 4(√6)      ...(v)  Adding  (iv), (v)        2(√x) = 6(√6)    or          x=54,  z=6 , y=24.  (One set of possible solution)!
$${x}−{y}+\sqrt{{z}}\left(\sqrt{{x}}−\sqrt{{y}}\right)=\mathrm{42}−\mathrm{6}\:\:{and} \\ $$$${y}−{z}+\sqrt{{x}}\left(\sqrt{{y}}−\sqrt{{z}}\right)=\mathrm{6}+\mathrm{30} \\ $$$$\Rightarrow \\ $$$$\:\:\left(\sqrt{{x}}−\sqrt{{y}}\right)\left(\sqrt{{x}}+\sqrt{{y}}+\sqrt{{z}}\right)=\mathrm{36}\:\:\:..\left({i}\right) \\ $$$$\:\left(\sqrt{{y}}−\sqrt{{z}}\right)\left(\sqrt{{x}}+\sqrt{{y}}+\sqrt{{z}}\right)=\mathrm{36}\:\:\:\:..\left({ii}\right) \\ $$$$\Rightarrow\:\:\:\sqrt{{x}}−\sqrt{{y}}\:=\:\sqrt{{y}}−\sqrt{{z}} \\ $$$${or}\:\:\:\sqrt{\boldsymbol{{x}}}+\sqrt{\boldsymbol{{z}}}=\mathrm{2}\sqrt{\boldsymbol{{y}}} \\ $$$${Adding}\:\left({i}\right),\left({ii}\right) \\ $$$$\:\:\left(\sqrt{{x}}−\sqrt{{z}}\right)\left(\mathrm{3}\sqrt{{y}}\right)=\mathrm{36}+\mathrm{36} \\ $$$$\Rightarrow\:\:\:\left(\sqrt{{x}}−\sqrt{{z}}\right)\left(\sqrt{{x}}+\sqrt{{z}}\right)=\frac{\mathrm{72}×\mathrm{2}}{\mathrm{3}} \\ $$$$\Rightarrow\:\:\:\:\:{x}−{z}\:=\:\mathrm{48}\:\:\:\:….\left({I}\right) \\ $$$$\:\:\:{Now}\:\:\:\:{y}−\sqrt{{xz}}\:=\:\mathrm{6} \\ $$$$\Rightarrow\:\:\:\:\:\:\left(\frac{\sqrt{{x}}+\sqrt{{z}}}{\mathrm{2}}\right)^{\mathrm{2}} −\sqrt{{xz}}\:=\:\mathrm{6} \\ $$$$\Rightarrow\:\:\:\:\:\left(\sqrt{{x}}−\sqrt{{z}}\right)^{\mathrm{2}} =\mathrm{24} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\sqrt{{x}}\:−\sqrt{{z}}\:=\:\mathrm{2}\sqrt{\mathrm{6}} \\ $$$${and}\:{using}\:\:\:{z}={x}−\mathrm{48}\:\:\:\:\left[{see}\:\left({I}\right)\right] \\ $$$$\:\:\:\:\:\sqrt{{x}}−\sqrt{{x}−\mathrm{48}}\:=\:\mathrm{2}\sqrt{\mathrm{6}}\:\:\:\:\:…..\left({iv}\right) \\ $$$$\:\:\:\:\:{Also}\:\:\:\frac{\mathrm{48}}{\:\sqrt{{x}}+\sqrt{{x}−\mathrm{48}}}\:=\:\mathrm{2}\sqrt{\mathrm{6}} \\ $$$$\Rightarrow\:\:\:\sqrt{{x}}+\sqrt{{x}−\mathrm{48}}\:\:=\:\mathrm{4}\sqrt{\mathrm{6}}\:\:\:\:\:\:…\left({v}\right) \\ $$$${Adding}\:\:\left({iv}\right),\:\left({v}\right) \\ $$$$\:\:\:\:\:\:\mathrm{2}\sqrt{{x}}\:=\:\mathrm{6}\sqrt{\mathrm{6}}\:\:\:\:{or}\:\:\: \\ $$$$\:\:\:\:\:{x}=\mathrm{54},\:\:{z}=\mathrm{6}\:,\:{y}=\mathrm{24}. \\ $$$$\left({One}\:{set}\:{of}\:{possible}\:{solution}\right)! \\ $$
Answered by 1549442205 last updated on 24/Jun/20

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