document.write( "Question 165194: 22.) Find he exact solution.\r
\n" ); document.write( "\n" ); document.write( "The height in feet for a ball thrown upward at 48 feet per second is given by
\n" ); document.write( " s(t)= - 16r^2 + 48t. Where t is the time in seconds after the ball is tossed. What is the maximum height that the ball will reach? \n" ); document.write( "
Algebra.Com's Answer #121770 by nerdybill(7384)\"\" \"About 
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s(t)= - 16t^2 + 48t
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\n" ); document.write( "The idea is that the equation describes a parabola. If the coefficient 'a' is negative, the parabola opens downward. Thus the vertex will give you the \"maximum\".
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\n" ); document.write( "The vertex form of a parabola is:
\n" ); document.write( "y= a(x-h)^2+k
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\n" ); document.write( "The idea is to convert the given equation into the above form.
\n" ); document.write( "s(t)= - 16t^2 + 48t
\n" ); document.write( "s(t)= -16(t^2 - 4t)
\n" ); document.write( "Completing the square, we have:
\n" ); document.write( "s(t)= -16(t^2 - 4t + 4) + 64
\n" ); document.write( "s(t)= -16(t-2)^2 + 64
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\n" ); document.write( "We now \"see\" that the vertex is at:
\n" ); document.write( "(h,k) = (2, 64)
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\n" ); document.write( "Which says, that at
\n" ); document.write( "2 seconds, the ball will reach the maximum height of 64 feet.
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