Question

im lost ... −16t2+80x−60=0

Solving for t,
t=(5±10−−√)2

Answer 1

why do you have mixed variables -__-

Answer 2

well simplify the problem -4(4t^2 - 20t +15)

Answer 3

Ah this is the a nswer i gave you earlier for the height?

Answer 4

yeah im lost

Answer 5

so using the GQF \[t = (20\pm \sqrt{(-20)^2-4\times4\times15})/(2 \times4)\]

\[t = (20 \pm \sqrt{16 \times10})/8 = (5\pm \sqrt{10})/2\]

Answer 6

umm yeah im already there

Answer 7

Screw it the equation th ing is broken

Answer 8

Use the quadratic formula to s olve for t

Answer 9

\[t=\frac{-b \pm \sqrt{b^2-4ac}}{2a}\]

Answer 10

I dont think ive learned that yet

Answer 11

in my class

Answer 12

Is this a physics problem or calculus?

Answer 13

calculus

Answer 14

You should've learned the quadratic formula back in algebra

Answer 15

woops....

Answer 16

lol

Answer 17

so i would just plug in the numbers that were found in the early part of the question?

Answer 18

\[ax^2+bx+c=0\], you can only use the quadratic formula when you have your equation like this

Answer 19

in this case you do, and you can also divide out a 4 from all the terms 16,80, and 60

Answer 20

\[-4t^2+20x-15=0\]
a=-4
b=20
c=-15

Answer 21

ok? so now I can solve by getting

Answer 22

by itself

Answer 23

T

Answer 24

no, use the quadratic formula as it is written above right now,
\[t=\frac{-b \pm \sqrt{b^2-4ac}}{2a}\]

Answer 25

\[t=\frac{-20 \pm \sqrt{20^2-4(-4)(-15)}}{2(-4)}\]

Answer 26

\[t=\frac{-20 \pm \sqrt{160}}{-8}=\frac{-20 \pm 4\sqrt{10}}{-8}=\frac{-5 \pm \sqrt{10}}{-2}=\frac{5 \pm \sqrt{10}}{2}\]

Answer 27

t= -20 sqrt 360/-8

Answer 28

look above

Answer 29

wow im way off!!

Answer 30

Remember to keep the positive and negative signs for a,b,c

Answer 31

so now I have 3.16227766/2 = 1.58113883

Answer 32

5+ or - = 1.58113883

Answer 33

\[t \approx .9189s, t \approx 4.081s\]

Answer 34

can you give me the all the numbers shown on your calculator

Answer 35

They are irrational numbers, there are infinitely many decimal places

Answer 36

Use the answer with the square root

Answer 37

That is accurate

Answer 38

no just the numbers shown on your calculator bcause I need the precise number

Answer 39

You can't get a precise number from an irrational number! Use
\[t=\frac{5 \pm \sqrt{10}}{2} s\]

Answer 40

That is the precise answer, any decimal answer is an approximation

Answer 41

what I mean is when plug the answers into the my computer it needs the closets thing to an approximate number

Answer 42

so it must have the all the numbers shown from the calculator for it to be correct

Answer 43

Your calculator can show hundreds of digits if you want it to

Answer 44

How many decimal places do you need?

Answer 45

\[t \approx 0.918861169916s, t \approx 4.08113883008s\]

Answer 46

like im using a standard calcultor so it only shows like 9 or 10 numbers

Answer 47

here are my instructions : For example, the fraction 2/3 is exact, while the decimals 0.67, 0.666666667 and 0.666666666666666666667 are all approximate values for 2/3.

Where an exact answer is called for, an approximate answer will be marked wrong.

Answer 48

So if you use a decimal here, you will be wrong

Answer 49

yup lol

Answer 50

Use the answer i gave you with the square root

Answer 51

so like t t= .9189 just sqrt it

Answer 52

...

Answer 53

\[t=\frac{5+\sqrt{10}}{2}, t=\frac{5-\sqrt{10}}{2}\]

Answer 54

Those are the exact answers for the time

Answer 55

ok got it , thanks sorry for the confusion !!