Question

I really don't know how to do this quadratic equation question :( Please help

Answer 1

?

Answer 2

The height (h) in metres of a football at time "t" is given by h = 23t - 5t^2. Does the football ever reach 27m ?

Answer 3

so your job is it solve
\[27=23t-5t^2\] if you can

Answer 4

yup

Answer 5

first step is to write as
\[5t^2-23t+27=0\] and now since it doesn't even ask for a solution you can just find
\[b^2-4ac\] and see if it is positive or negative

Answer 6

ohhhhhhhhhhhhhhh and if it's negative then the answer is "no" right?

Answer 7

in this case you get
\[23^2-4\times 5\times 27=-11\] so there is no solution

Answer 8

I mean if the radical has a negative number in in..

Answer 9

right

Answer 10

Ahhh okay thank you thank you :))))

Answer 11

you could also just solve
\[x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}\] but you will see you get a negative number under the radical, so no answer

Answer 12

Right ! I totally get it ~ thanks so much :D:

Answer 13

yw