document.write( "Question 939490: Find the parabola that passes through points (3.5,10), (11,60), and (15,90) \n" ); document.write( "
Algebra.Com's Answer #572480 by MathLover1(20849)\"\" \"About 
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Find the parabola that passes through points (3.5,10), (11,60), and (15,90)\r
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\n" ); document.write( "\n" ); document.write( "\"y=ax%5E2%2Bbx%2Bc\" ...we need to find coefficients \"a\", \"b\", and \"c\"; so, use given points and set the system of three quations \r
\n" ); document.write( "\n" ); document.write( " for point (3.5,10) we have\r
\n" ); document.write( "\n" ); document.write( "\"10=a%283.5%29%5E2%2Bb%283.5%29%2Bc\"\r
\n" ); document.write( "\n" ); document.write( "\"10=12.25a%2B%283.5%29b%2Bc\"................eq.1\r
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\n" ); document.write( "\n" ); document.write( " for point(11,60) we have\r
\n" ); document.write( "\n" ); document.write( "\"60=a%2811%29%5E2%2Bb%2811%29%2Bc\"\r
\n" ); document.write( "\n" ); document.write( "\"60=121a%2B11b%2Bc\"................eq.2\r
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\n" ); document.write( "\n" ); document.write( "for point (15,90) we have\r
\n" ); document.write( "\n" ); document.write( "\"90=a%2815%29%5E2%2Bb%2815%29%2Bc\"\r
\n" ); document.write( "\n" ); document.write( "\"90=225a%2B15b%2Bc\"................eq.3\r
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\n" ); document.write( "\n" ); document.write( "solve the system:\r
\n" ); document.write( "\n" ); document.write( "\"10=12.25a%2B%283.5%29b%2Bc\"................eq.1
\n" ); document.write( "\"60=121a%2B11b%2Bc\"................eq.2
\n" ); document.write( "\"90=225a%2B15b%2Bc\"................eq.3
\n" ); document.write( "------------------------------------------------------substitute eq.1 from eq.2\r
\n" ); document.write( "\n" ); document.write( "\"60-10=121a%2B11b%2Bc-%2812.25a%2B%283.5%29b%2Bc%29\"................eq.2\r
\n" ); document.write( "\n" ); document.write( "\"50=121a%2B11b%2Bcross%28c%29-12.25a-%283.5%29b-cross%28c%29\"\r
\n" ); document.write( "\n" ); document.write( "\"50=108.75a%2B7.5b\" ...solve for \"a\"\r
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\n" ); document.write( "\n" ); document.write( "\"50-7.5b=108.75a\"\r
\n" ); document.write( "\n" ); document.write( "\"a=%2850-7.5b%29%2F108.75\".............1a\r
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\n" ); document.write( "\n" ); document.write( "substitute eq.2 from eq.3\r
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\n" ); document.write( "\n" ); document.write( "\"90-60=225a%2B15b%2Bc-%28121a%2B11b%2Bc%29\"................eq.3\r
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\n" ); document.write( "\n" ); document.write( "\"30=225a%2B15b%2Bc-121a-11b-c\"\r
\n" ); document.write( "\n" ); document.write( "\"30=104a%2B4b\"...solve for \"a\"\r
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\n" ); document.write( "\n" ); document.write( "\"a=%2830-4b%29%2F104\"............2a\r
\n" ); document.write( "\n" ); document.write( "left sides in 1a and 2a are equal, so set right sides equal and solve for \"b\"\r
\n" ); document.write( "\n" ); document.write( "\"%2850-7.5b%29%2F108.75=%2830-4b%29%2F104\" ...cross multiply\r
\n" ); document.write( "\n" ); document.write( "\"104%2850-7.5b%29=108.75%2830-4b%29\"\r
\n" ); document.write( "\n" ); document.write( "\"5200-780b=3262.5-435b\"\r
\n" ); document.write( "\n" ); document.write( "\"5200-3262.5=780b+-435b\"\r
\n" ); document.write( "\n" ); document.write( "\"1937.5=345b\"\r
\n" ); document.write( "\n" ); document.write( "\"b=1937.5%2F345\"\r
\n" ); document.write( "\n" ); document.write( "\"b=5.615942028985507\"\r
\n" ); document.write( "\n" ); document.write( "\"b=5.6\"\r
\n" ); document.write( "\n" ); document.write( "now find \"a\"\r
\n" ); document.write( "\n" ); document.write( "\"a=%2830-4b%29%2F104\"............2a\r
\n" ); document.write( "\n" ); document.write( "\"a=%2830-4%2A5.6%29%2F104\"\r
\n" ); document.write( "\n" ); document.write( "\"a=%2830-22.4%29%2F104\"\r
\n" ); document.write( "\n" ); document.write( "\"a=7.6%2F104\"\r
\n" ); document.write( "\n" ); document.write( "\"a=76%2F1040\"\r
\n" ); document.write( "\n" ); document.write( "\"a=0.0730769230769231\"\r
\n" ); document.write( "\n" ); document.write( "\"a=0.07\"\r
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\n" ); document.write( "\n" ); document.write( "now we can find \"c\"\r
\n" ); document.write( "\n" ); document.write( "\"10=12.25a%2B%283.5%29b%2Bc\"................eq.1\r
\n" ); document.write( "\n" ); document.write( "\"10=12.25%2A0.07%2B%283.5%295.6%2Bc\"\r
\n" ); document.write( "\n" ); document.write( "\"10=0.8575%2B19.6%2Bc\"\r
\n" ); document.write( "\n" ); document.write( "\"10=20.4575%2Bc\"\r
\n" ); document.write( "\n" ); document.write( "\"10-20.4575=c\"\r
\n" ); document.write( "\n" ); document.write( "\"c=-10.4575\"\r
\n" ); document.write( "\n" ); document.write( "\"c=-10.5\"\r
\n" ); document.write( "\n" ); document.write( "so, your equation is:\r
\n" ); document.write( "\n" ); document.write( "\"highlight%28y=0.07x%5E2%2B5.6x-10.5%29\"
\n" ); document.write( "(3.5,10), (11,60), and (15,90)\r
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