document.write( "Question 577267: How do I graph and determine the solution set of:
\n" ); document.write( "x=7-2y
\n" ); document.write( "y=3x\r
\n" ); document.write( "\n" ); document.write( "What i tried to do was set them to zero, but I didn't know what else to do..please help! \n" ); document.write( "

Algebra.Com's Answer #370130 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
These are 2 straight lines and the solution
\n" ); document.write( "is their intersection. Since 2 straight lines
\n" ); document.write( "can only intersect at 1 point, there is only
\n" ); document.write( "1 solution.
\n" ); document.write( "------------
\n" ); document.write( "Get both lines into the standard form:
\n" ); document.write( "(1) $\"+x+=+7+-+2y+\"$
\n" ); document.write( "(1) $\"+x+%2B+2y+=+7+\"$
\n" ); document.write( "and
\n" ); document.write( "(2) $\"+y+=+3x+\"$
\n" ); document.write( "(2) $\"+3x+-+y+=+0+\"$
\n" ); document.write( "----------------
\n" ); document.write( "Now multiply both sides of (2) by $\"+2+\"$ ,
\n" ); document.write( "and add the equations
\n" ); document.write( "(1) $\"+x+%2B+2y+=+7+\"$
\n" ); document.write( "(2) $\"+6x+-2y+=+0+\"$
\n" ); document.write( " $\"+7x+=+7+\"$
\n" ); document.write( " $\"+x+=+1+\"$
\n" ); document.write( "Now plug this value back into either (1) or (2)
\n" ); document.write( "(2) $\"+3%2A1+-+y+=+0+\"$
\n" ); document.write( "(2) $\"+-y+=+-3+\"$
\n" ); document.write( "(2) $\"+y+=+3+\"$
\n" ); document.write( "The solution is (1,3)
\n" ); document.write( "Here's a plot of the lines:
\n" ); document.write( " $\"+graph%28+400%2C+400%2C+-10%2C+10%2C+-10%2C+10%2C+3x%2C+-%281%2F2%29%2Ax+%2B+7%2F2+%29+\"$ \n" ); document.write( "

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