document.write( "Question 1089704: 21. (See Week 4 Lecture page “Solving Rational Inequalities” for a starting point.) Suppose that a factory’s cost (in dollars) for making x cars is
\n" ); document.write( "C(x) = 7020x + 8460
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\n" ); document.write( "𝐶′(𝑥)= 7020𝑥+8460 /𝑥
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Algebra.Com's Answer #704079 by ikleyn(52803) $\"\"$ $\"About$

You can put this solution on YOUR website!
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document.write( "From the condition, this phrase \"the average cost per car is no more than $7200\"\r\n" );
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document.write( "means that an inequality takes place\r\n" );
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document.write( " <= 7200.    (1)\r\n" );
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document.write( "And they want you solve this inequality for x.  \r\n" );
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document.write( "To solve it, multiply both sides by x.  Since x is positive, by its meaning, you can do it without problems. You will get\r\n" );
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document.write( "7020x + 8460 <= 7200x.\r\n" );
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document.write( "Simplify it by subtracting the number 7020 from both sides. You will get\r\n" );
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document.write( "8640 <= 7200x - 7020,   \r\n" );
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document.write( "8640 <= 180x,\r\n" );
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document.write( "x >=  = 48.\r\n" );
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document.write( "So,  x >= 48  is your solution and is your answer.\r\n" );
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