Question 1071819
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Suppose that x and y are positive numbers with xy=1/9, x(y+1)=7/9, y(x+1)=5/18. What is the value of (x+1)(y+1)?
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<pre>
x(y+1)=7/9  ====>  y+1 = {{{7/(9x)}}}.


y(x+1)=5/18  ====>  x+1 = {{{5/(18*y)}}}.


====> (x+1)*(y+1) = {{{7/(9x))}}}.{{{5/(18*y)}}} = {{{35/(9*18*xy)}}} = 


                    now replace xy in the denominator by {{{1/9}}}, and you will get 

= {{{35/(9*18*(1/9))}}} = {{{35/18}}}.
</pre>

Solved.