Quadratic word problem

[omgineedhelp123]

I was taught the factoring way, so I don’t understand how to get the zeros without doing that

 

[Deleted member 4993]

No, no, no. I beat you to this post so you have to remove yours. Thank you.

Sitting in the dark dank corner your eye-sight is gone. Look at the time stamp of post #4. Posted at 2:09 AM today (GMT I suppose). When did you post yours?

 

[omgineedhelp123]

This is an example of how I factor but with this equation it’s so hard to factor

 

[Deleted member 4993]

h = -4.9*t^2+ 30.6*t → 0 = -4.9*t^2+ 30.6*t → t * (30.6 - 4.9 *t) = 0

There are two values of 't' that will satisfy the equation above. What are those?

Looks like a copy-paste of response #4 including "→". I know someone who hates those signs.

 

[omgineedhelp123]

Subhotosh Khan can you help?

 

[omgineedhelp123]

Jomo can you help?

 

[Deleted member 4993]

Subhotosh Khan can you help?

Jomo gave an example. Read it carefully.

Here is an example. If x(x-3) = 0 then with either x=0 or x-3 = 0. Well x=0 when x=0 and x-3 = 0 when x=3. So the answers are x=0 or x=3.

You have factored correctly

t * (30.6 - 4.9 *t)

- now "interpret" your factors according to Jomo's example.

 

[omgineedhelp123]

I never learned to interpret it. My teacher just told us to factor and then find the zeros

 

[Deleted member 4993]

I never learned to interpret it. My teacher just told us to factor and then find the zeros

Jomo in his response (#16 - that I quoted) gave you an example of interpretation. Please read that carefully - then tell us what part (if any) of that response (#16) is missing you.

 

[Steven G]

The two factors are t and 30.6 - 4.9 *t.

Which value for t makes the 1st factor equal to 0 (very easy solution)?
Which value for t makes the 2nd factor equal to 0?

 

[omgineedhelp123]

t-0= 0 and I don’t know

 

[omgineedhelp123]

I’m trying but I still don’t understand

 

[Steven G]

30.6 - 4.9 *t.

what do you subtract from 30.6 to get 0? What are you subtracting from 30.6. Equate them.

 

[omgineedhelp123]

I did this example from before

 

[omgineedhelp123]

You subtract 30.6 to get 0

 

[Steven G]

You subtract 30.6 to get 0

Can you now answer my 2nd question (what are you subtracting from 30.6?)

 

[omgineedhelp123]

I am subtracting 30.6 from 0. I understood how the zeros for x(x-3)= 0,3 but I just don’t get this one

 

[Steven G]

If 30.6 - 4.9 *t = 0, then 4.9t = 30.6. Then t = 30.6/4.9 = ....

 

[Deleted member 4993]

If 30.6 - 4.9 *t = 0, then 4.9t = 30.6. Then t = 30.6/4.9 = ....

Alternatively:

30.6 - 4.9 *t = 0

30.6 - 4.9 *t - 30.6 = 0 - 30.6

- 4.9 *t = - 30.6

t = - 30.6/(- 4.9)

t = 30.6/(4.9) ....... and continue......

 

[omgineedhelp123]

Oh but isn’t that just simplify the equation?