document.write( "Question 78478:
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document.write( "I am confused on these type of problems, please help. \r\n" );
document.write( "If f(x)=x(x+3)(x-1), use interval notation to give all values of\r\n" );
document.write( "   x where f(x)>0\r\n" );
document.write( "a. (-3,1)\r\n" );
document.write( "b. (-3,0)È(1,¥)\r\n" );
document.write( "c. (1,3)\r\n" );
document.write( "d. (0,1)È(3,¥)
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Algebra.Com's Answer #56300 by Edwin McCravy(20056)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "I am confused on these type of problems, please help. \r\n" );
document.write( "If f(x)=x(x+3)(x-1), use interval notation to give all values of\r\n" );
document.write( "   x where f(x)>0\r\n" );
document.write( "a. (-3,1)\r\n" );
document.write( "b. (-3,0)È(1,¥)\r\n" );
document.write( "c. (1,3)\r\n" );
document.write( "d. (0,1)È(3,¥)\r\n" );
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document.write( "f(x) = x(x + 3)(x - 1)\r\n" );
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document.write( "The critical values are 0, -3 and 1\r\n" );
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document.write( "Mark those on a number line:\r\n" );
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document.write( "---------o-----------o---o--------\r\n" );
document.write( "-5  -4  -3  -2  -1   0   1   2   3 \r\n" );
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document.write( "That divides the number line into 4 parts:\r\n" );
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document.write( " (-¥,-3), (-3,0), (0,1), (1,¥) \r\n" );
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document.write( "Make this chart:\r\n" );
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document.write( "     interval | (-¥,-3) | (-3,0) | (0,1) | (1,¥) |  \r\n" );
document.write( "test value, t |    -4   |   -1   |   .5  |    2  |\r\n" );
document.write( "         f(t) |   -20   |    4   | -.875 |   10  |\r\n" );
document.write( " sign of f(t) |     -   |    +   |    -  |    +  |\r\n" );
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document.write( "Since we are looking for the solution set of f(x) > 0\r\n" );
document.write( "we are looking for the intervals in which the sign of f(x)\r\n" );
document.write( "is positive. These are (-3,0) and (1,0), so the solution set\r\n" );
document.write( "is\r\n" );
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document.write( "                  (-3,0) È (1,¥)\r\n" );
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document.write( "which is choice b.\r\n" );
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document.write( "Edwin
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