document.write( "Question 68734: y=2x
\n" ); document.write( "x+y=12 \n" ); document.write( "
Algebra.Com's Answer #48933 by tutorcecilia(2152)\"\" \"About 
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y=2x
\n" ); document.write( "x+y=12
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\n" ); document.write( "y=2x
\n" ); document.write( "x+y=12 [solve for y so that both equations match]
\n" ); document.write( "y=-x+12
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\n" ); document.write( "y=2x
\n" ); document.write( "(2)(y=-x+12) [multiply by a number that will cause the cancellation of a variable]
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\n" ); document.write( "1y=2x
\n" ); document.write( "2y=-2x+24
\n" ); document.write( "_________
\n" ); document.write( "3y=24 [solve for y]
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\n" ); document.write( "3y/3=24/3
\n" ); document.write( "y=8
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\n" ); document.write( "Solve for x
\n" ); document.write( "y=2x [let y=8]
\n" ); document.write( "8=2x
\n" ); document.write( "8/2=2x/2
\n" ); document.write( "4=x
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\n" ); document.write( "check by plugging x=4 and y=8 back into the original equations\r
\n" ); document.write( "\n" ); document.write( "y=2x
\n" ); document.write( "8=2(4)
\n" ); document.write( "8=8 [checks out]
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\n" ); document.write( "x+y=12
\n" ); document.write( "(4)+(8)=12
\n" ); document.write( "12=12 [also checks out]\r
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