document.write( "Question 1183267: Hi can you please help me with this question. A golf ball is hit from the top of a tee. The quadratic equation y=-5x^2 + 20x + 0.05 describes its height,y, in metres as time,x, in seconds passes. Determine how long the ball is in the air. Thanks for the help \n" ); document.write( "
Algebra.Com's Answer #813493 by MathLover1(20850)\"\" \"About 
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\n" ); document.write( "\n" ); document.write( "A golf ball is hit from the top of a tee. The quadratic equation
\n" ); document.write( "\"y=-5x%5E2+%2B+20x+%2B+0.05+\"\r
\n" ); document.write( "\n" ); document.write( "describes its height, \"y\", in metres as time,\"x\", in seconds passes. \r
\n" ); document.write( "\n" ); document.write( "Determine how long the ball is in the air. \r
\n" ); document.write( "\n" ); document.write( "First, you have to determine how long it will take for the golf ball to reach its maximum height.\r
\n" ); document.write( "\n" ); document.write( "so, rewrite equation in vertex form\r
\n" ); document.write( "\n" ); document.write( "\"y=a%28x-h%29%5E2%2Bk\" where \"h\" and \"k\" are coordinates of vertex\r
\n" ); document.write( "\n" ); document.write( "\"y=-5x%5E2+%2B+20x+%2B+0.05+\"....group
\n" ); document.write( "\"y=%28-5x%5E2+%2B+20x%29+%2B+0.05+\"....factor out \"-5\"
\n" ); document.write( "\"y=-5%28x%5E2+-4x%29+%2B+0.05+\"
\n" ); document.write( "\"y=-5%28x%5E2+-4x%2Bb%5E2%29+-%28-5b%5E2%29%2B+0.05+\"....\"b=4%2F2=2\"
\n" ); document.write( "\"y=-5%28x%5E2+-4x%2B2%5E2%29+%2B5%2A2%5E2%2B+0.05+\"
\n" ); document.write( "\"y=-5%28x+-2%29%5E2+%2B20%2B+0.05+\"
\n" ); document.write( "\"y=-5%28x+-2%29%5E2+%2B20.05+\"\r
\n" ); document.write( "\n" ); document.write( "=> \"h=2\" and \"k=20.05\"
\n" ); document.write( "to reach its maximum height of \"20.05\", it will take \"2\" seconds\r
\n" ); document.write( "\n" ); document.write( "The time in the air is twice the one I found solving for t where the height is maximum.\r
\n" ); document.write( "\n" ); document.write( "the ball is \"4\" seconds in the air\r
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