document.write( "Question 477801: • Post a response to the following: If you are looking at a graph of a quadratic equation y = ax2 + bx + c, how do you determine where the solutions to 0 = ax2 + bx + c are? Compare this with solving the equation using the quadratic formula. \n" ); document.write( "

Algebra.Com's Answer #327436 by Theo(13342) $\"\"$ $\"About$

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it's when the graph crosses the x-axis.
\n" ); document.write( "that gives you the value of x when y is equal to 0.
\n" ); document.write( "the graph will show you the approximate value of x.
\n" ); document.write( "the quadratic formula will give you the exact value of x.
\n" ); document.write( "the only reason the graph gives you the approximate value of x is because the resolution of the graph is usually not fine enough to pinpoint the exact value.
\n" ); document.write( "here's an example:
\n" ); document.write( "equation is 5x^2 + 3x - 13 = 0
\n" ); document.write( "here's the graph.
\n" ); document.write( " $\"graph%28300%2C300%2C-10%2C10%2C-100%2C100%2C5x%5E2+%2B+3x+-+13%29\"$
\n" ); document.write( "you can see the approximate locations of the roots.
\n" ); document.write( "they are somewhere around x = -2 and x = 1
\n" ); document.write( "the detail isn't fine enough to pinpoint them exactly though.
\n" ); document.write( "the quadratic formula gets you to the exact solution
\n" ); document.write( "using that formula, you get:
\n" ); document.write( "x = -1.940121947
\n" ); document.write( "x = 1.340121947
\n" ); document.write( "the roots of the quadratic are the value of x when the value of y is equal to 0.\r
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