document.write( "Question 1049249: Herman arranged a game of water balloon volleyball for his daughter’s birthday party. Suppose the balloon has a height of h metres, t seconds after it is tossed, as defined by h = -5t^2 + 12t + 1.
\n" ); document.write( "a) Write an equation that shows how many seconds will pass before the balloon hits the ground. Solve this equation,rounded to the nearest hundredth of a second.
\n" ); document.write( "b) what is the maximum height reached by the balloon? When does it reach this height?
\n" ); document.write( "

Algebra.Com's Answer #664811 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
(a)
\n" ); document.write( "\"+h+=+-5t%5E2+%2B+12t+%2B+1+\"
\n" ); document.write( "---------------------------
\n" ); document.write( "The ball is tossed at \"+t+=+0+\"
\n" ); document.write( "This gives you:
\n" ); document.write( "\"+h%280%29+=+-5%2A0%5E2+%2B+12%2A0+%2B+1+\"
\n" ); document.write( "\"+h%280%29+=+1+\"
\n" ); document.write( "They are saying that the ball is tossed from a height
\n" ); document.write( "of \"+1+\" meter
\n" ); document.write( "---------------------------
\n" ); document.write( "You want to know the time in seconds when
\n" ); document.write( "\"+h+=+0+\" ( balloon hits the ground )
\n" ); document.write( "\"+-5t%5E2+%2B+12t+%2B+1+=+0+\"
\n" ); document.write( "Use the quadratic formula
\n" ); document.write( "\"+t+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"
\n" ); document.write( "\"+a+=+-5+\"
\n" ); document.write( "\"+b+=+12+\"
\n" ); document.write( "\"+c+=+1+\"
\n" ); document.write( "\"+t+=+%28+-12+%2B-+sqrt%28+12%5E2-4%2A%28-5%29%2A1+%29%29%2F%282%2A%28-5%29%29+\"
\n" ); document.write( "\"+t+=+%28+-12+%2B-+sqrt%28+144+%2B+20+%29%29%2F%28-10%29+\"
\n" ); document.write( "\"+t+=+%28+-12+%2B-+sqrt%28+164+%29%29%2F%28-10%29+\"
\n" ); document.write( "\"+t+=+%28+-12+-+12.8062+%29+%2F+%28-10%29+\" ( time has to come out positive )
\n" ); document.write( "\"+t+=+24.8062+%2F+10+\"
\n" ); document.write( "\"+t+=+2.4806+\" sec
\n" ); document.write( "The balloon hits the ground in 2.48 sec
\n" ); document.write( "----------------------------------------
\n" ); document.write( "(b)
\n" ); document.write( "The \"+t+\"-value at the maximum is:
\n" ); document.write( "\"+t%5Bmax%5D+=+-b%2F%282a%29+\"
\n" ); document.write( "\"+t%5Bmax%5D+=+-12%2F%28+2%2A%28-5%29%29+\"
\n" ); document.write( "\"+t%5Bmax%5D+=+1.2+\"
\n" ); document.write( "Plug this value back into equation \"+h%28t%29+\"
\n" ); document.write( "\"+h+=+-5t%5E2+%2B+12t+%2B+1+\"
\n" ); document.write( "\"+h%281.2%29+=+-5%2A1.2%5E2+%2B+12%2A1.2+%2B+1+\"
\n" ); document.write( "\"+h%281.2%29+=+-5%2A1.44+%2B+14.4+%2B+1+\"
\n" ); document.write( "\"+h%281.2%29+=+-7.2+%2B+15.4+\"
\n" ); document.write( "\"+h%281.2%29+=+8.2+\"
\n" ); document.write( "The maximm height is 8.2 m which it will
\n" ); document.write( "reach in 1.2 sec
\n" ); document.write( "------------------------
\n" ); document.write( "check:
\n" ); document.write( "Here's the plot:
\n" ); document.write( "\"+graph%28+400%2C+400%2C+-4%2C+4%2C+-4%2C+10%2C+-5x%5E2+%2B+12x+%2B+1+%29+\"
\n" ); document.write( "My numbers look pretty close\r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );