document.write( "Question 122238: A baseball player hits a ball into the air. The ball's height above the ground, in metres, t seconds after being hit, is approximated by h(t)=1+13t-5t^2. Algebraically determine the time when the ball first reaches a height of 9 m. \n" ); document.write( "
Algebra.Com's Answer #89802 by algebrapro18(249)\"\" \"About 
You can put this solution on YOUR website!
well all you have to do here is plug 9 in for h(t) and solve for t.
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\n" ); document.write( "\n" ); document.write( "9 = 1 + 13t -5t^2 ---> Combine like terms
\n" ); document.write( "5t^2-13t+8 = 0 ---> factor
\n" ); document.write( "(5t-8)(t-1)=0
--->set each factor to zero and solve\r
\n" ); document.write( "\n" ); document.write( "5t-8=0 ---> add 8 to both sides
\n" ); document.write( "5t = 8 ---> divide both sides by 5
\n" ); document.write( "t = 8/5
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\n" ); document.write( "\n" ); document.write( "t-1 = 0 --> add 1 to both sides
\n" ); document.write( "t = 1
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\n" ); document.write( "\n" ); document.write( "so the ball reaches the height of 9 meters 1 second after it was hit. \n" ); document.write( "
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