document.write( "Question 1071819: 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)? \n" ); document.write( "
Algebra.Com's Answer #686734 by rothauserc(4718)\"\" \"About 
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1) xy = 1/9
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\n" ); document.write( "3) y(x+1) = 5/18
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\n" ); document.write( "using equation 2
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\n" ); document.write( "xy + x = 7/9
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\n" ); document.write( "use equation 1 and substitute for xy in equation 2
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\n" ); document.write( "(1/9) + x = (7/9)
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\n" ); document.write( "x = (7/9) - (1/9) = 6/9 = 2/3
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\n" ); document.write( "use equation 1 and equation 3, subsitute for xy in equation 3
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\n" ); document.write( "yx + y = 5/18
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\n" ); document.write( "(1/9) + y = (5/18) - (1/9) = (3/18) = (1/6)
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\n" ); document.write( "Note that multiplication is communitive, that is, yx = xy
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\n" ); document.write( "(x+1) * (y+1) = ( (2/3) + 1 ) * ( (1/6) + 1 ) = (5/3) * (7/6) = (35 / 18)
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