document.write( "Question 78478: \r\n" );
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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document.write( "
Algebra.Com's Answer #56300 by Edwin McCravy(20056)![]() ![]() You can put this solution on YOUR website! \r\n" ); 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" ); document.write( "\r\n" ); document.write( "-------------------------------------\r\n" ); document.write( "\r\n" ); document.write( "f(x) = x(x + 3)(x - 1)\r\n" ); document.write( "\r\n" ); document.write( "The critical values are 0, -3 and 1\r\n" ); document.write( "\r\n" ); document.write( "Mark those on a number line:\r\n" ); document.write( "\r\n" ); document.write( "---------o-----------o---o--------\r\n" ); document.write( "-5 -4 -3 -2 -1 0 1 2 3 \r\n" ); document.write( "\r\n" ); document.write( "That divides the number line into 4 parts:\r\n" ); document.write( "\r\n" ); document.write( " (-¥,-3), (-3,0), (0,1), (1,¥) \r\n" ); document.write( "\r\n" ); document.write( "Make this chart:\r\n" ); document.write( "\r\n" ); 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" ); document.write( "\r\n" ); document.write( "\r\n" ); 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" ); document.write( "\r\n" ); document.write( " (-3,0) È (1,¥)\r\n" ); document.write( "\r\n" ); document.write( "which is choice b.\r\n" ); document.write( "\r\n" ); document.write( "Edwin\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |