document.write( "Question 63942: 1.true or false:
\n" ); document.write( "-3x-6y=-21
\n" ); document.write( "9x+6y=-9\r
\n" ); document.write( "
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\n" ); document.write( "\n" ); document.write( "2.which is addition method and substitution method?\r
\n" ); document.write( "\n" ); document.write( "x=7y+14
\n" ); document.write( "2x+15y=-75\r
\n" ); document.write( "\n" ); document.write( "4x-7y=14
\n" ); document.write( "2x+15y=-75\r
\n" ); document.write( "\n" ); document.write( "thank you so much \n" ); document.write( "
Algebra.Com's Answer #44771 by tutorcecilia(2152)\"\" \"About 
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1.true or false:
\n" ); document.write( "-3x-6y=-21
\n" ); document.write( "9x+6y=-9
\n" ); document.write( "___________ [Subtract the equations]
\n" ); document.write( "6x=-30
\n" ); document.write( "x=-5 [Substitute and solve for y]
\n" ); document.write( ".
\n" ); document.write( "
\n" ); document.write( "-3(-5)-6y=-21
\n" ); document.write( "15-6y=-21
\n" ); document.write( "-6y=-21-15
\n" ); document.write( "-6y=-36
\n" ); document.write( "y=6
\n" ); document.write( ".
\n" ); document.write( "checking:
\n" ); document.write( "9(-5)+6(6)=-9
\n" ); document.write( "-45+36 =-9
\n" ); document.write( "-9=-9, so the answer is true, x=-5 and y=6 for both equations.\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
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