document.write( "Question 430100: During one month, a homeowner used 500 units of electricity and 100 units of gas for a total cost of 352.00. the next month, 400 units of electricity and 150 units of gas were used for a total cost of 304.00. Find the cost per unit of gas \n" ); document.write( "
Algebra.Com's Answer #298680 by mananth(16946)\"\" \"About 
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\n" ); document.write( "gas cost x
\n" ); document.write( "electricity cost y\r
\n" ); document.write( "\n" ); document.write( "100x+500y=352 .............1
\n" ); document.write( "150x+400y=304 .............2
\n" ); document.write( "Eliminate y
\n" ); document.write( "multiply (1)by -4
\n" ); document.write( "Multiply (2) by 5
\n" ); document.write( "-400x-2000y=-1408
\n" ); document.write( "750x+2000y=1520
\n" ); document.write( "Add the two equations
\n" ); document.write( "350x= 112
\n" ); document.write( "/350
\n" ); document.write( "x=0.32 gas unit cost
\n" ); document.write( "plug value of x in (1)
\n" ); document.write( "100x+500y=352
\n" ); document.write( "32+500y=352
\n" ); document.write( "500y=352-32
\n" ); document.write( "500y=320
\n" ); document.write( "y=0.64 electricity cost
\n" ); document.write( "CHECK
\n" ); document.write( "
\n" ); document.write( "100 x + 500 y = 352
\n" ); document.write( "32 320 = 352
\n" ); document.write( " 352 = 352
\n" ); document.write( " \n" ); document.write( "
\n" );