document.write( "Question 130147: An astronaut on the moon throws a baseball upward. The height h of the ball, in feet, x seconds after the ball is thrown is given by the equation. \r
\n" ); document.write( "\n" ); document.write( "h+-2.7x^2+30x+6.5\r
\n" ); document.write( "\n" ); document.write( "After how many seconds is the ball 12 feet above the moon's surface? \n" ); document.write( "

Algebra.Com's Answer #95077 by stanbon(75887) $\"\"$ $\"About$

You can put this solution on YOUR website!
The height h of the ball, in feet, x seconds after the ball is thrown is given by the equation.
\n" ); document.write( "h(t)= -2.7x^2+30x+6.5
\n" ); document.write( "After how many seconds is the ball 12 feet above the moon's surface?
\n" ); document.write( "-----------
\n" ); document.write( "Let the height be 12 and solve for \"x\".
\n" ); document.write( "-2.7x^2 + 30x + 6.5 = 12
\n" ); document.write( "-2.7x^2 + 30x - 4.5 = 0
\n" ); document.write( "x = [-30 +- sqrt(900 -4*-2.7*-4.5)]/-5.4\r
\n" ); document.write( "\n" ); document.write( "x = [-30 +- sqrt(851.4)]/-5.4\r
\n" ); document.write( "\n" ); document.write( "x = [-30 +- 29.17876]/-5.4\r
\n" ); document.write( "\n" ); document.write( "x = 10.96 seconds and x = 0.1521 seconds
\n" ); document.write( "==========================
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "

\n" );