SOLUTION: my equation is 9x squared + 6x=-1 please explain this to me...or even this one h= -16t squared + 40t where t is the time in seconds and h is the height of the ball. will the ball e

Algebra ->  Complex Numbers Imaginary Numbers Solvers and Lesson -> SOLUTION: my equation is 9x squared + 6x=-1 please explain this to me...or even this one h= -16t squared + 40t where t is the time in seconds and h is the height of the ball. will the ball e      Log On


   

Question 462474: my equation is 9x squared + 6x=-1 please explain this to me...or even this one h= -16t squared + 40t where t is the time in seconds and h is the height of the ball. will the ball ever reach 22 feet?
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

9x%5E2+%2B+6x=-1.........factor
9x%5E2+%2B+6x+%2B1=0
9x%5E2+%2B+3x+%2B+3x%2B1=0
%289x%5E2+%2B+3x%29+%2B+%283x%2B1%29=0
%283x+%2B+1%29%283x%2B1%29=0

3x+%2B+1=0...->...3x+=-1..->...x+=-1%2F3...double solution


3x%283x+%2B+1%29+%2B+%283x%2B1%29=0
h=+-16t%5E2+%2B+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%5E2+%2B+40t....solve for t
16t%5E2+-40t%2B22ft=0
t+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
t+=+%28-%28-40%29+%2B-+sqrt%28+%28-40%29%5E2-4%2A16%2A22+%29%29%2F%282%2A16%29+
t+=+%2840+%2B-+sqrt%28+1600-1408+%29%29%2F32+
t+=+%2840+%2B-+sqrt%28+192%29%29%2F32+
t+=+%2840+%2B-+13.9%29%2F32+
find positive solution...time cannot be negative
t+=+%2840+%2B+13.9%29%2F32+
t+=+%2853.9%29%2F32+
t+=+1.7s
or
t+=+%2840+-+13.9%29%2F32+
t+=+%2826.1%29%2F32+
t+=0.8s