document.write( "Question 1017770: Find a quadratic model for the set of values (-2, -20)(0,-4) (4, -20) if u can, can u show your work please thnx so much, trying to see if i did it wright. \n" ); document.write( "
Algebra.Com's Answer #634333 by ankor@dixie-net.com(22740)\"\" \"About 
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Find a quadratic model for the set of values (-2, -20)(0,-4) (4, -20)
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\n" ); document.write( "Develop an equation from each set of points using the form: ax^2 + bx + c = y
\n" ); document.write( "Find a, b, c. The 2nd set of values, 0.-4, tells us c=-4 (x=0)
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\n" ); document.write( "x=-2; y=-20
\n" ); document.write( "4a - 2b - 4 = -20
\n" ); document.write( "4a - 2b = -20 + 4
\n" ); document.write( "4a - 2b = -16
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\n" ); document.write( "x=4; y=-20
\n" ); document.write( "16a + 4b - 4 = -20
\n" ); document.write( "16a + 4b = -20 + 4
\n" ); document.write( "16a + 4b = -16
\n" ); document.write( "simplify, divide by 2
\n" ); document.write( "8a + 2b = -8
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\n" ); document.write( "Use elimination, add the two equations
\n" ); document.write( "4a - 2b = -16
\n" ); document.write( "8a + 2b = -8
\n" ); document.write( "--------------adding eliminates b, find a
\n" ); document.write( "12a = -24
\n" ); document.write( "a = -24/12
\n" ); document.write( "a = -2
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\n" ); document.write( "Find b using the simplified equatin 8a + 2b = -8
\n" ); document.write( "8(-2) + 2b = -6
\n" ); document.write( "-16 + 2b = -8
\n" ); document.write( "2b = -8 + 16
\n" ); document.write( "2b = 8
\n" ); document.write( "b = 4
\n" ); document.write( ":
\n" ); document.write( "The equation y = -2x^2 + 4x - 4
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\n" ); document.write( "You can confirm this for yourself, replace the x with given values and see if they equal the given y \n" ); document.write( "
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