document.write( "Question 75316This question is from textbook Alegbra 2 An Incremental Development
\n" ); document.write( ": Please help to solve \r
\n" ); document.write( "\n" ); document.write( "x + 3y = 7
\n" ); document.write( "xy = 2 \n" ); document.write( "
Algebra.Com's Answer #54158 by ankor@dixie-net.com(22740)\"\" \"About 
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Please help to solve
\n" ); document.write( "x + 3y = 7
\n" ); document.write( "xy = 2
\n" ); document.write( ":
\n" ); document.write( "Arrange the 1st equation to = x
\n" ); document.write( "x + 3y = 7
\n" ); document.write( "x = 7 - 3y
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\n" ); document.write( "Substitute (7-3y) for x in the 2nd equation, xy = 2:
\n" ); document.write( "y(7-3y) = 2
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\n" ); document.write( "7y - 3y^2 = 2
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\n" ); document.write( "0 = 3y^2 - 7y + 2; a quadratic equation that factors to:
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\n" ); document.write( "(3y - 1)(y - 2) = 0
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\n" ); document.write( "3y = +1
\n" ); document.write( "y = +1/3
\n" ); document.write( "and
\n" ); document.write( "y = +2
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\n" ); document.write( "Find x when y = 1/3:
\n" ); document.write( "x = 7 - 3y
\n" ); document.write( "x = 7 - 3(1/3)
\n" ); document.write( "x = 7 -1
\n" ); document.write( "x = 6
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\n" ); document.write( "Find x when y = 2
\n" ); document.write( "x = 7 - 3(2)
\n" ); document.write( "x = 7 - 6
\n" ); document.write( "x = 1
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\n" ); document.write( "Test both sets of solutions in xy = 2
\n" ); document.write( "x=6,y=(1/3): 6(1/3) = 2
\n" ); document.write( "and
\n" ); document.write( "x=1, y=2: 1(2) = 2 also
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\n" ); document.write( "How about this? Did you follow this OK? Any questions?
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