document.write( "Question 182960: It costs $1.70 to buy supplies to make a fork and $1.30 to buy supplies to make a spoon. The store sells the fork for $5.60 and the spoon for $5.40. They spent $37.90 on materials for forks and spoons. They sold the finished product for $147.20. How many forks and how many spoons did they make?\r
\n" ); document.write( "\n" ); document.write( "I did 1.70x + 1.30y = 37.90 as one of my equations\r
\n" ); document.write( "\n" ); document.write( "5.60x + 5.40y = 147.20 for my other\r
\n" ); document.write( "\n" ); document.write( "I have tried substitution and get tangled up with the decimals
\n" ); document.write( "I have tried addition and get messed up. Seems I get decimal answers and can't seem to work it into a whole fork or whole spoon without it being a decimal. What am I doing wrong, or are my equations not correct and this is where Im going wrong.
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Algebra.Com's Answer #137355 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
You can solve this system with the decimal values, but I always find it easier to get rid of the decimal numbers. To do this, simply multiply both sides of the equations by 100 (which will move EVERY decimal place 2 spots to the right)\r
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\n" ); document.write( "\n" ); document.write( "\"1.70x+%2B+1.30y+=+37.90\" Start with the first equation.\r
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\n" ); document.write( "\n" ); document.write( "\"100%281.70x%2B1.30y%29=100%2837.90%29\" Multiply both sides by 100 to clear out the decimals.\r
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\n" ); document.write( "\n" ); document.write( "\"170x%2B130y=3790\" Distribute and multiply.\r
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\n" ); document.write( "\n" ); document.write( "So the new first equation is \"170x%2B130y=3790\"\r
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\n" ); document.write( "\n" ); document.write( "\"5.60x+%2B+5.40y+=+147.20\" Move onto the second equation.\r
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\n" ); document.write( "\n" ); document.write( "\"100%285.60x%2B5.40y%29=100%28147.20%29\" Multiply both sides by 100 to clear out the decimals.\r
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\n" ); document.write( "\n" ); document.write( "\"560x%2B540y=14720\" Distribute and multiply.\r
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\n" ); document.write( "\n" ); document.write( "So the new second equation is \"560x%2B540y=14720\"\r
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\n" ); document.write( "\n" ); document.write( "So we have the system of equations:\r
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\n" ); document.write( "\n" ); document.write( "\"system%28170x%2B130y=3790%2C560x%2B540y=14720%29\"\r
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\n" ); document.write( "\n" ); document.write( "Let's use substitution to solve this system.\r
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\n" ); document.write( "\n" ); document.write( "Now in order to solve this system by using substitution, we need to solve (or isolate) one variable. I'm going to solve for y.\r
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\n" ); document.write( "\n" ); document.write( "So let's isolate y in the first equation\r
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\n" ); document.write( "\n" ); document.write( "\"170x%2B130y=3790\" Start with the first equation\r
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\n" ); document.write( "\n" ); document.write( "\"130y=3790-170x\" Subtract \"170x\" from both sides\r
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\n" ); document.write( "\n" ); document.write( "\"130y=-170x%2B3790\" Rearrange the equation\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28-170x%2B3790%29%2F%28130%29\" Divide both sides by \"130\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28%28-170%29%2F%28130%29%29x%2B%283790%29%2F%28130%29\" Break up the fraction\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28-17%2F13%29x%2B379%2F13\" Reduce\r
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\n" ); document.write( "\n" ); document.write( "Since \"y=%28-17%2F13%29x%2B379%2F13\", we can now replace each \"y\" in the second equation with \"%28-17%2F13%29x%2B379%2F13\" to solve for \"x\"\r
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\n" ); document.write( "\n" ); document.write( "\"560x%2B540highlight%28%28%28-17%2F13%29x%2B379%2F13%29%29=14720\" Plug in \"y=%28-17%2F13%29x%2B379%2F13\" into the second equation. In other words, replace each \"y\" with \"%28-17%2F13%29x%2B379%2F13\". Notice we've eliminated the \"y\" variables. So we now have a simple equation with one unknown.\r
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\n" ); document.write( "\n" ); document.write( "\"560x%2B%28540%29%28-17%2F13%29x%2B%28540%29%28379%2F13%29=14720\" Distribute \"540\" to \"%28-17%2F13%29x%2B379%2F13\"\r
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\n" ); document.write( "\n" ); document.write( "\"560x-%289180%2F13%29x%2B204660%2F13=14720\" Multiply\r
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\n" ); document.write( "\n" ); document.write( " Multiply EVERY term by the LCD 13. This will eliminate the fractions \r
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\n" ); document.write( "\n" ); document.write( "\"7280x-9180x%2B204660=191360\" Multiply and simplify\r
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\n" ); document.write( "\n" ); document.write( "\"-1900x%2B204660=191360\" Combine like terms on the left side\r
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\n" ); document.write( "\n" ); document.write( "\"-1900x=191360-204660\" Subtract 204660 from both sides\r
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\n" ); document.write( "\n" ); document.write( "\"-1900x=-13300\" Combine like terms on the right side\r
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\n" ); document.write( "\n" ); document.write( "\"x=%28-13300%29%2F%28-1900%29\" Divide both sides by -1900 to isolate x\r
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\n" ); document.write( "\n" ); document.write( "\"x=7\" Divide\r
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\n" ); document.write( "\n" ); document.write( "-----------------First Answer------------------------------\r
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\n" ); document.write( "\n" ); document.write( "So the first part of our answer is: \"x=7\"\r
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\n" ); document.write( "\n" ); document.write( "Since we know that \"x=7\" we can plug it into the equation \"y=%28-17%2F13%29x%2B379%2F13\" (remember we previously solved for \"y\" in the first equation).\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28-17%2F13%29x%2B379%2F13\" Start with the equation where \"y\" was previously isolated.\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28-17%2F13%29%287%29%2B379%2F13\" Plug in \"x=7\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=-119%2F13%2B379%2F13\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"y=20\" Combine like terms and reduce. \r
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\n" ); document.write( "\n" ); document.write( "-----------------Second Answer------------------------------\r
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\n" ); document.write( "\n" ); document.write( "So the second part of our answer is: \"y=20\"\r
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\n" ); document.write( "\n" ); document.write( "-----------------Summary------------------------------\r
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\n" ); document.write( "\n" ); document.write( "So our answers are:\r
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\n" ); document.write( "\n" ); document.write( "\"x=7\" and \"y=20\"\r
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\n" ); document.write( "\n" ); document.write( "So this means that they made 7 forks and 20 spoons\r
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