document.write( "Question 1113803: Can this system by solved by substitution?
\n" ); document.write( "6x + 7y = -9
\n" ); document.write( "-4x - 5y = 5 \n" ); document.write( "

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\n" ); document.write( "Can this system by solved by substitution?
\n" ); document.write( "6x + 7y = -9
\n" ); document.write( "-4x - 5y = 5
\n" ); document.write( "

You don't have to deal with ANNOYING fractions by solving for a variable right away. IGNORE anyone who tells you to do that.
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document.write( "In this particular case, ADD the 2 equations to get eq (iii) in the form of: 2x + 2y = - 4
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document.write( "Reduce eq (iii) by dividing it by 2 to get: x + y = - 2____x = - 2 - y
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document.write( "Now, substitute this value for x in any of the 2 equations. I chose eq (ii), and got: - 4(- 2 - y) - 5y = 5
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document.write( "8 + 4y - 5y = 5
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document.write( "4y - 5y = 5 - 8
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document.write( "- y = - 3
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document.write( "You then substitute 3 for y in any of the original equations to get x. I chose eq (ii), and got: - 4x - 5(3) = 5
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document.write( "- 4x - 15 = 5
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document.write( "- 4x = 20
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