document.write( "Question 256232: A rocket launched from ground level with an initial velocity of 224 ft/s. When will the rocket reach a height of 528 ft? I know that h=vt-16t^2 will be used. So what happens after I plug it all in? 528=224t-16t^2? \n" ); document.write( "
Algebra.Com's Answer #188425 by Greenfinch(383)\"\" \"About 
You can put this solution on YOUR website!
It is simpler dividing through by 16
\n" ); document.write( "33 = 14t -t^2 so
\n" ); document.write( "t^2 - 14t + 33 = 0\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation \"at%5E2%2Bbt%2Bc=0\" (in our case \"-1t%5E2%2B14t%2B-33+=+0\") has the following solutons:
\n" ); document.write( "
\n" ); document.write( " \"t%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca\"
\n" ); document.write( "
\n" ); document.write( " For these solutions to exist, the discriminant \"b%5E2-4ac\" should not be a negative number.
\n" ); document.write( "
\n" ); document.write( " First, we need to compute the discriminant \"b%5E2-4ac\": \"b%5E2-4ac=%2814%29%5E2-4%2A-1%2A-33=64\".
\n" ); document.write( "
\n" ); document.write( " Discriminant d=64 is greater than zero. That means that there are two solutions: \"+x%5B12%5D+=+%28-14%2B-sqrt%28+64+%29%29%2F2%5Ca\".
\n" ); document.write( "
\n" ); document.write( " \"t%5B1%5D+=+%28-%2814%29%2Bsqrt%28+64+%29%29%2F2%5C-1+=+3\"
\n" ); document.write( " \"t%5B2%5D+=+%28-%2814%29-sqrt%28+64+%29%29%2F2%5C-1+=+11\"
\n" ); document.write( "
\n" ); document.write( " Quadratic expression \"-1t%5E2%2B14t%2B-33\" can be factored:
\n" ); document.write( " \"-1t%5E2%2B14t%2B-33+=+-1%28t-3%29%2A%28t-11%29\"
\n" ); document.write( " Again, the answer is: 3, 11.\n" ); document.write( "Here's your graph:
\n" ); document.write( "\"graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+-1%2Ax%5E2%2B14%2Ax%2B-33+%29\"

\n" ); document.write( "\n" ); document.write( "This gives t = 3 and t = 11. So it will pass 528 feet after three seconds, carry on until it runs out of speed after 7 seconds when it starts to drop until it passes 528 feet on the way down after 11 seconds hits the ground after 14 seconds
\n" ); document.write( "
\n" );