Math, asked by alisha8763, 11 months ago

if 2log (x+y)=3log3+logx+logy,then show that x/y+y/x=25​

Answers

Answered by Ashal
13

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Answered by Anonymous
26

Solution :-

 \sf 2log(x + y) = 3 log3 +  logx +  logy \\  \\  \\ \sf \longrightarrow  log(x + y)^2 =  log3^3 +  logx +  logy \\  \\  \\  \boxed{ \bf \because m.loga =  log a^m } \\  \\  \\  \sf \longrightarrow  log(x + y)^2 = log3^3xy \\  \\  \\  \sf \longrightarrow  log(x + y)^2 = log27xy \\  \\  \\  \bf \underline{ Cancelling \: log \: on \: both \: sides} \\  \\  \\  \sf \longrightarrow  (x + y)^2 = 27xy \\  \\  \\ \sf \longrightarrow x^2 + y^2 + 2xy = 27xy \\ \\  \\  \bf \because (x + y)^2 =  {x}^{2} +  {y}^{2} + 2xy \\  \\  \bf \underline{Transpose \: 2xy \: to \: RHS} \\  \\  \\  \sf \longrightarrow x^2 + y^2 = 27xy - 2xy \\  \\  \\  \sf \longrightarrow x^2 + y^2 = 25xy

Divide every term of the equation by xy

 \sf \longrightarrow  \dfrac{x^2}{xy} +  \dfrac{y^2 }{xy} =  \dfrac{25xy}{xy} \\  \\  \\  \sf \longrightarrow  \dfrac{x}{y} +  \dfrac{y}{x} = 25

Hence shown.

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