document.write( "Question 197346: If you are looking at a graph of a quadratic equation, how do you determine where the solutions are? \n" ); document.write( "
Algebra.Com's Answer #147969 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "If you have a quadratic equation such as\r\n" );
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document.write( "\"Ax%5E2%2BBx%2BC=0\"\r\n" );
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document.write( "you realize that the solutions to that equation\r\n" );
document.write( "is the solution to this system of equations:\r\n" );
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document.write( "\"system%28y=Ax%5E2%2BBx%2BC%2Cy=0%29\"\r\n" );
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document.write( "The line whose equation is y=0 is the x-axis.\r\n" );
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document.write( "So you graph the first equation, then look to\r\n" );
document.write( "see the values of x where the graph crosses the\r\n" );
document.write( "x-axis.\r\n" );
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document.write( "So the answer is \"the x-intercepts\" or\r\n" );
document.write( "\"the values of x at which the graph crosses the\r\n" );
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document.write( "Example:\r\n" );
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document.write( "Solve the quadratic equation:\r\n" );
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document.write( "\"4x%5E2-8x-21=0\"\r\n" );
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document.write( "The solutions to this are the x-values of the\r\n" );
document.write( "solution to:\r\n" );
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document.write( "\"system%28y=4x%5E2-8x-21%2Cy=0%29\"\r\n" );
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document.write( "So we graph the first equation by finding\r\n" );
document.write( "points:\r\n" );
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document.write( "(-2,11), (-1,9), (0,-21), (1,-25), (2,-21), (3,-9), (4,11)\r\n" );
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document.write( "\"graph%28400%2C500%2C-3%2C5%2C-26%2C12%2C4x%5E2-8x-21%29\"\r\n" );
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document.write( "You can see the solutions to \"4x%5E2-8x-21=0\"\r\n" );
document.write( "by observing that the graph crosses the x-axis\r\n" );
document.write( "at \"x=-1%261%2F2\" and at \"x=3%261%2F2\".\r\n" );
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document.write( "So those are the solutions to \"4x%5E2-8x-21=0\".\r\n" );
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document.write( "Edwin
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