document.write( "Question 733322: The height h(t), in feet, of an airborn tee-shirt t seconds after being launched can be approximated by h(t)=-15t^2+105t+10, 0<= t <=10. Find the time when the shirt will reach a fan 190ft above ground level? \n" ); document.write( "

Algebra.Com's Answer #448357 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"+h%28t%29+=-15t%5E2%2B105t%2B10+\"$
\n" ); document.write( " $\"+h%28t%29+=+190+\"$ ft
\n" ); document.write( " $\"+190+=-15t%5E2%2B105t%2B10+\"$
\n" ); document.write( " $\"+-15t%5E2+%2B+105t+-+180+=+0+\"$
\n" ); document.write( " $\"+-t%5E2+%2B+7t+-+12+=+0+\"$
\n" ); document.write( "Use 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( " $\"+a+=+-1+\"$
\n" ); document.write( " $\"+b+=+7+\"$
\n" ); document.write( " $\"+c+=+-12+\"$
\n" ); document.write( " $\"+t+=+%28+-7+%2B-+sqrt%28+7%5E2+-+4%2A%28-1%29%2A%28-12%29+%29%29+%2F+%282%2A%28-1%29%29+\"$
\n" ); document.write( " $\"+t+=+%28+-7+%2B-+sqrt%28+49+-+48+%29%29+%2F+%28-2%29+\"$
\n" ); document.write( " $\"+t+=+%28+-7+%2B-+sqrt%28+1+%29%29+%2F+%28-2%29+\"$
\n" ); document.write( " $\"+t+=+%28+-7+%2B+1+%29+%2F+%28-2%29+\"$
\n" ); document.write( " $\"+t+=+3+\"$
\n" ); document.write( "also
\n" ); document.write( " $\"+t+=+%28+-7+-+1+%29+%2F+%28-2%29+\"$
\n" ); document.write( " $\"+t+=+4+\"$
\n" ); document.write( "There are 2 times when it is 190 ft above ground, 3 sec and 4 sec
\n" ); document.write( "check:
\n" ); document.write( " $\"+graph%28+400%2C+400%2C+-2%2C+10%2C+-200%2C+20%2C+-15%2Ax%5E2+%2B+105x+-+180+%29+\"$
\n" ); document.write( " \n" ); document.write( "

\n" );