document.write( "Question 424941: I really need help on solving this word problem. It would be GREATLY appreciated if someone could help me!\r
\n" ); document.write( "\n" ); document.write( "- During one month, a homeowner used 500 units of electricity and 100 units of gas for a total utility bill of $88. The next month, 400 units of electricity and 150 units of gas were used for a total bill of $76. What is the unit cost of both types of energy?\r
\n" ); document.write( "\n" ); document.write( "Thank you so much ! \n" ); document.write( "
Algebra.Com's Answer #296075 by mananth(16946)\"\" \"About 
You can put this solution on YOUR website!
let unit cost of electricity be $x
\n" ); document.write( "let unit cost of gas be $y\r
\n" ); document.write( "\n" ); document.write( "500x+100y=88.............1
\n" ); document.write( "400x+150y=76.............2
\n" ); document.write( "
\n" ); document.write( "multiply (1)by -3
\n" ); document.write( "Multiply (2) by 2
\n" ); document.write( "-1500x-300y=-264
\n" ); document.write( "800x+300y=152
\n" ); document.write( "
\n" ); document.write( "Add the two equations
\n" ); document.write( "-700x=-112
\n" ); document.write( "/-700
\n" ); document.write( "x=0.16 electricity unit cost 16 cents
\n" ); document.write( "
\n" ); document.write( "plug value of x in (1)
\n" ); document.write( "
\n" ); document.write( "500x+100y=88
\n" ); document.write( "80+100y =88
\n" ); document.write( "100y=88-80
\n" ); document.write( "100y=8
\n" ); document.write( "y=0.08 gas unit cost 8 cents
\n" ); document.write( " \n" ); document.write( "
\n" );