document.write( "Question 68749: Solve the system by substitution.
\n" ); document.write( " 3x – y = –7
\n" ); document.write( " x + y = –9\r
\n" ); document.write( "\n" ); document.write( "Help!! I am pulling my hair out! :0) I need help with substitution, I am not understanding. Can someone please help me. Thanks. \n" ); document.write( "
Algebra.Com's Answer #48946 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
Solve the system by substitution.
\n" ); document.write( "3x – y = –7
\n" ); document.write( "x + y = –9
\n" ); document.write( "--------------
\n" ); document.write( "Solve either equation for y:
\n" ); document.write( "y=3x+7
\n" ); document.write( "Substitute that into the OTHER equation to get:
\n" ); document.write( "x+(3x+7)=-9
\n" ); document.write( "4x=-16
\n" ); document.write( "x=-4
\n" ); document.write( "---------
\n" ); document.write( "Substitute that into EITHER of the equations to solve for \"x\":
\n" ); document.write( "x+-4=-9
\n" ); document.write( "x=-5
\n" ); document.write( "----------
\n" ); document.write( "Answer: (-4,-5)
\n" ); document.write( "You could check this in the other quation:
\n" ); document.write( "3x – y = –7
\n" ); document.write( "3(-4)-(-5)=-7
\n" ); document.write( "12+5=7
\n" ); document.write( "7=7
\n" ); document.write( "---------
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
\n" ); document.write( " \n" ); document.write( "
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