Question 950715

{{{s = -14t^2 + 280t}}}
For what values of {{{t}}} will the object be more than {{{1050 }}}feet above the ground?

{{{1050 > -14t^2 + 280t}}}

{{{14t^2-280t +1050 > 0}}}..............simplify, both sides divide by {{{14}}}

{{{t^2-20t +75 > 0}}}......factor completely

{{{t^2-15t -5t+75 > 0}}}

{{{(t^2-15t) -(5t-75) > 0}}}

{{{t(t-15) -5(t-15) > 0}}}

{{{(t-5) (t-15)>=0}}}

solutions:
{{{(t-5)>=0}}}=>{{{t>=5}}}

{{{(t-15)>=0}}}=>{{{t>=15}}}

combined:

{{{5<x<15}}}