document.write( "Question 972146: For the function f(x) = x3 + 3x2 – 70x – 144, f(–9) = 0, f(–2) = 0, and f(8) = 0. What are the solutions to the equation x3 + 3x2 = 70x + 144 = 0?
\n" ); document.write( "A)
\n" ); document.write( " x = –8, x = 2, and x = 9
\n" ); document.write( "B)
\n" ); document.write( " x = –9, x = –2, and x = 8
\n" ); document.write( "C)
\n" ); document.write( " x = –8, x = –2, and x = 9
\n" ); document.write( "D)
\n" ); document.write( " x = –9, x = –8, and x = –2 \n" ); document.write( "
Algebra.Com's Answer #594524 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
For the function f(x) = x3 + 3x2 – 70x – 144, f(–9) = 0, f(–2) = 0, and f(8) = 0. What are the solutions to the equation x3 + 3x2 = 70x + 144 = 0?
\n" ); document.write( "A)
\n" ); document.write( " x = –8, x = 2, and x = 9
\n" ); document.write( "B)
\n" ); document.write( " x = –9, x = –2, and x = 8
\n" ); document.write( "C)
\n" ); document.write( " x = –8, x = –2, and x = 9
\n" ); document.write( "D)
\n" ); document.write( " x = –9, x = –8, and x = –2
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document.write( "This is a giveaway problem to anyone who understands it.\r\n" );
document.write( "I'll go through it to show why it is a giveaway problem:\r\n" );
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document.write( "f(x) = x3 + 3x2 – 70x – 144\r\n" );
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document.write( "f(–9) = 0\r\n" );
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document.write( "That tells us that if you plug in (-9) for x in\r\n" );
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document.write( "f(x) = x3 + 3x2 – 70x – 144, we get 0\r\n" );
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document.write( "That means that -9 is a solution to \r\n" );
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document.write( "f(x) = x3 + 3x2 – 70x – 144 = 0\r\n" );
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document.write( "Checking to make sure that he has told us the truth:\r\n" );
document.write( "[Not necessary if we trust the problem-maker :) ]\r\n" );
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document.write( "f(-9) = (-9)3 + 3(-9)2 – 70(-9) – 144\r\n" );
document.write( "f(-9) = -729 + 3(81) + 630 - 144\r\n" );
document.write( "f(-9) = -729 + 243 + 630 - 144\r\n" );
document.write( "f(-9) = 0  \r\n" );
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document.write( "The problem-maker told us the truth! f(-9) = 0.\r\n" );
document.write( "So we'll trust him to have told us the truth on the others.\r\n" );
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document.write( "------------------------------------------------\r\n" );
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document.write( "f(–2) = 0\r\n" );
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document.write( "That tells us that if we plug in (-2) for x in\r\n" );
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document.write( "f(x) = x3 + 3x2 – 70x – 144, we get 0, that is:\r\n" );
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document.write( "That means that -2 is a solution to \r\n" );
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document.write( "f(x) = x3 + 3x2 – 70x – 144 = 0\r\n" );
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document.write( "We'll trust him that the above does give 0\r\n" );
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document.write( "---------------------------------------------\r\n" );
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document.write( "f(8) = 0\r\n" );
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document.write( "That tells us that if we plug in (8) for x in\r\n" );
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document.write( "f(x) = x3 + 3x2 – 70x – 144, we get 0, that is:\r\n" );
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document.write( "That means that 8 is a solution to \r\n" );
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document.write( "f(x) = x3 + 3x2 – 70x – 144 = 0\r\n" );
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document.write( "We'll trust him that the above does give 0\r\n" );
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document.write( "---------------------------------------------\r\n" );
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document.write( "So the solutions are –9, –2, and 8\r\n" );
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document.write( "Because telling us that f(–9) = 0, f(–2) = 0, and f(8) = 0, tells\r\n" );
document.write( "us the solutions, what values we must plug into f(x) to get 0, and since \r\n" );
document.write( "f(x) equals to x3 + 3x2 – 70x – 144, those values in the parentheses\r\n" );
document.write( "are what values we must plug into x3 + 3x2 – 70x – 144 to get 0.\r\n" );
document.write( "So they have to be solutions to the equationn x3 + 3x2 – 70x – 144 = 0.\r\n" );
document.write( "See why it's a giveaway problem? -- like \"Who's buried in Grant's tomb?\" :)\r\n" );
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document.write( "Edwin

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