document.write( "Question 112312: Walt made an extra $9000 last year from a part-time job. He invested part of the money at a 9% annual rate of interest, and the rest at an 8% annual rate of interest. At the end of the year, he made a total of $770 in interest. How much was invested at 8%? \n" ); document.write( "
Algebra.Com's Answer #81931 by checkley71(8403)\"\" \"About 
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.08X+.09(9000-X)=770
\n" ); document.write( ".08X+810-.09X=770
\n" ); document.write( "-.01X=770-810
\n" ); document.write( "-.01X=-40
\n" ); document.write( "X=-40/-.01
\n" ); document.write( "X=4000 AMOUNT INVESTED @ 8%
\n" ); document.write( "9000-4000=5000 INVESTED @ 9%
\n" ); document.write( "PROOF
\n" ); document.write( ".08*4000+.09*5000=770
\n" ); document.write( "320+450=770
\n" ); document.write( "770=770
\n" ); document.write( "
\n" );