Question 224653
Solve by introducing a substitution that transforms equation to quadratic form.

{{{(3y)^-2   + (y)^-1  -4=0}}}


Step 1.  Let {{{x=1/y}}}


Step 2.  Substitute x into {{{(3y)^-2   + (y)^-1  -4=0}}}


{{{9x^2+x-4=0}}}


Step 3.  To solve, use the given quadratic formula below


{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} 


where a=9, b=1, and c=-4


*[invoke quadratic "x", 9, 1, -4 ]


Since {{{x1=0.61342}}} , then {{{y1=1/x1=1.63}}}


And {{{x2=-0.724533}}} , then {{{y2=1/x2=-1.38}}}


Step 4.  The solution is 1.63 and -1.38


I hope the above steps were helpful.


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Good luck in your studies!


Respectfully,
Dr J