Question 462474

{{{9x^2 + 6x=-1}}}.........factor

{{{9x^2 + 6x +1=0}}}

{{{9x^2 + 3x + 3x+1=0}}}

{{{(9x^2 + 3x) + (3x+1)=0}}}

{{{(3x + 1)(3x+1)=0}}}


{{{3x + 1=0}}}...->...{{{3x =-1}}}..->...{{{x =-1/3}}}...double solution



{{{3x(3x + 1) + (3x+1)=0}}}

{{{h= -16t^2 + 40t}}}... where {{{t}}} is the {{{time}}} in seconds and {{{h}}} is the {{{height}}} of the ball. 


will the ball ever reach {{{22 ft}}}? 

{{{22ft= -16t^2 + 40t}}}....solve for {{{t}}}

{{{16t^2 -40t+22ft=0}}}

{{{t = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}

{{{t = (-(-40) +- sqrt( (-40)^2-4*16*22 ))/(2*16) }}}

{{{t = (40 +- sqrt( 1600-1408 ))/32 }}}

{{{t = (40 +- sqrt( 192))/32 }}}

{{{t = (40 +- 13.9)/32 }}}

find positive solution...time cannot be negative

{{{t = (40 + 13.9)/32 }}}

{{{t = (53.9)/32 }}}

{{{t = 1.7s}}}

or

{{{t = (40 - 13.9)/32 }}}

{{{t = (26.1)/32 }}}

{{{t =0.8s}}}