document.write( "Question 683994: A programmer is writing the code for a new interactive basketball game. As a result, she is using quadratic relations to model the path of the ball. During the game, when a ball is shot, the path it follows is modeled by the quadratic relation,h= -0.2d^2 + 3d + 6 , where h represented the height of the ball above the ground and d represented the distance of the ball from the shooter. Both distances are measured in feet.\r
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\n" ); document.write( "A rim of a basketball net is 10 feet high. For what horizontal distance was the ball above the rim of the basketball net?\r
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Algebra.Com's Answer #423860 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
How high was the ball when the shooter shot it?\r
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\n" ); document.write( "\n" ); document.write( "\"h=+-0.2d%5E2+%2B+3d+%2B+6\"\r
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\n" ); document.write( "\n" ); document.write( "\"h=+-0.2%280%29%5E2+%2B+3%280%29+%2B+6\" ... Plug in d = 0 (since the ball is zero ft away from the player when it is shot)\r
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\n" ); document.write( "\n" ); document.write( "\"h=+-0.2%280%29+%2B+3%280%29+%2B+6+\"\r
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\n" ); document.write( "\n" ); document.write( "\"h=+0+%2B+0+%2B+6+\"\r
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\n" ); document.write( "\n" ); document.write( "\"h+=+6\"\r
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\n" ); document.write( "\n" ); document.write( "So the ball is 6 ft off the ground when the shooter shot it.\r
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\n" ); document.write( "\n" ); document.write( "What was the maximum height obtained by the ball?\r
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\n" ); document.write( "\n" ); document.write( "To answer this question, we need to find the vertex\r
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\n" ); document.write( "\n" ); document.write( "First replace all 'h' terms with y. Then replace all 'd' terms with 'x'\r
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\n" ); document.write( "\n" ); document.write( "Now find the x coordinate of the vertex\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+-b%2F%282a%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+-3%2F%282%28-0.2%29%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+7.5\"\r
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\n" ); document.write( "\n" ); document.write( "Then plug this in to find the y coordinate of the vertex\r
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\n" ); document.write( "\n" ); document.write( "\"y+=+-0.2d%5E2+%2B+3d+%2B+6\"\r
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\n" ); document.write( "\n" ); document.write( "\"y+=+-0.2%287.5%29%5E2+%2B+3%287.5%29+%2B+6\"\r
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\n" ); document.write( "\n" ); document.write( "\"y+=+-0.2%2856.25%29+%2B+3%287.5%29+%2B+6\"\r
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\n" ); document.write( "\n" ); document.write( "\"y+=+-11.25+%2B+22.5+%2B+6\"\r
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\n" ); document.write( "\n" ); document.write( "\"y+=+17.25\"\r
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\n" ); document.write( "\n" ); document.write( "The y coordinate of the vertex represents the highest point.\r
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\n" ); document.write( "\n" ); document.write( "So the max height is 17.25 ft.\r
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\n" ); document.write( "\n" ); document.write( "A rim of a basketball net is 10 feet high. For what horizontal distance was the ball above the rim of the basketball net? \r
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\n" ); document.write( "\n" ); document.write( "Plug in h = 10 and solve for d\r
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\n" ); document.write( "\n" ); document.write( "\"h+=+-0.2d%5E2+%2B+3d+%2B+6\"\r
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\n" ); document.write( "\n" ); document.write( "\"10+=+-0.2d%5E2+%2B+3d+%2B+6\"\r
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\n" ); document.write( "\n" ); document.write( "\"0+=+-0.2d%5E2+%2B+3d+%2B+6+-+10\"\r
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\n" ); document.write( "\n" ); document.write( "\"0+=+-0.2d%5E2+%2B+3d+-+4\"\r
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\n" ); document.write( "\"-0.2d%5E2+%2B+3d+-+4+=+0\"\r
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\n" ); document.write( "\n" ); document.write( "\"10%28-0.2d%5E2+%2B+3d+-+4%29+=+10%2A0\"\r
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\n" ); document.write( "\n" ); document.write( "\"-2d%5E2+%2B+30d+-+40+=+0\"\r
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\n" ); document.write( "\n" ); document.write( "\"-1%28-2d%5E2+%2B+30d+-+40%29+=+-1%2A0\"\r
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\n" ); document.write( "\n" ); document.write( "\"2d%5E2+-+30d+%2B+40+=+0\"\r
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\n" ); document.write( "\n" ); document.write( "\"2%28d%5E2+-+15d+%2B+20%29+=+0\"\r
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\n" ); document.write( "\n" ); document.write( "\"d%5E2+-+15d+%2B+20+=+0%2F2\"\r
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\n" ); document.write( "\n" ); document.write( "\"d%5E2+-+15d+%2B+20+=+0\"\r
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\n" ); document.write( "\n" ); document.write( "Now use the quadratic formula to solve for d\r
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\n" ); document.write( "\n" ); document.write( "\"d+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"d+=+%28-%28-15%29%2B-sqrt%28%28-15%29%5E2-4%281%29%2820%29%29%29%2F%282%281%29%29\" Plug in \"a+=+1\", \"b+=+-15\", \"c+=+20\"\r
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\n" ); document.write( "\n" ); document.write( "\"d+=+%2815%2B-sqrt%28225-%2880%29%29%29%2F%282%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"d+=+%2815%2B-sqrt%28145%29%29%2F2\"\r
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\n" ); document.write( "\n" ); document.write( "\"d+=+%2815%2Bsqrt%28145%29%29%2F2\" or \"d+=+%2815-sqrt%28145%29%29%2F2\"\r
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\n" ); document.write( "\n" ); document.write( "\"d+=+13.520797\" or \"d+=+1.479203\"\r
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\n" ); document.write( "\n" ); document.write( "So the distance is either \"d+=+13.520797\" or \"d+=+1.479203\", which means that the distance it travels about 13.520797 - 1.479203 = 12.041594 feet horizontally when the ball is above the 10 ft rim.
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