document.write( "Question 523948: I do not understand the process to solve this problem:\r
\n" ); document.write( "\n" ); document.write( "A model rocket is launched with an initial upward velocity of 50 m/s . The rocket's height h (in meters) after t seconds is given by the following.
\n" ); document.write( "h=50t-5t^2\r
\n" ); document.write( "\n" ); document.write( "Find all values of for which the rocket's height is 30 meters. \n" ); document.write( "
Algebra.Com's Answer #347479 by nerdybill(7384)\"\" \"About 
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A model rocket is launched with an initial upward velocity of 50 m/s . The rocket's height h (in meters) after t seconds is given by the following.
\n" ); document.write( "h=50t-5t^2
\n" ); document.write( "Find all values of for which the rocket's height is 30 meters.
\n" ); document.write( ".
\n" ); document.write( "simply set h to 30 and solve for t:
\n" ); document.write( "h=50t-5t^2
\n" ); document.write( "30=50t-5t^2
\n" ); document.write( "5t^2 + 30 = 50t
\n" ); document.write( "5t^2 - 50t + 30 = 0
\n" ); document.write( "t^2 - 10t + 6 = 0
\n" ); document.write( "Since you can't factor, you must apply the \"quadratic formula\" to get:
\n" ); document.write( "t = {0.641, 9.359} seconds.
\n" ); document.write( ".
\n" ); document.write( "That is, on the way UP at:
\n" ); document.write( "0.641 seconds it'll be at 30 meters
\n" ); document.write( "then again, on the way back DOWN at:
\n" ); document.write( "9.359 seconds \n" ); document.write( "
\n" );