Question

Can someone please check my work on this math question? please? I'll fan and give a medal!!

Answer 1

Please help me solve this equation –
-4.9t2 + 24.5t + 117.6 = 0

Answer 2

@mjdennis can you please try to help me?

Answer 3

Have you tried using quadratic formula?

Answer 4

no sir... i cant figure out how to use it

Answer 5

Quadratic Formula: \(ax^2+bx+c=0\Longrightarrow x=\dfrac{\text-b\pm\sqrt{b^2-4ac}}{2a}\)

Here, you have \(-4.9t^2 + 24.5t + 117.6=0\)

So that would make \(a=-4.9,~b=24.5,~c=117.6\)

Now plug in values and use calculator to get the answer. Is that clear?

Answer 6

ok so
-24.5+/-\/([24.5^2]-4*-4.9*117.6
x=-------------------------------
2(-4.9)

Answer 7

@ganeshie8 can you try to help me please?

Answer 8

have you tried solving what you just posted above?

Answer 9

so so... I can't figure it out

Answer 10

hold on, I think i got it

Answer 11

Let's focus on the part in red first.
\[\Large x=\frac{-b \pm \sqrt{{\color{red}{b^2-4ac}}}}{2a}\]
This is the discriminant

So we have \(\Large b^2-4ac\). Let's plug in the values for a,b,c.

a = -4.9
b = 24.5
c = 117.6

\[\Large b^2-4ac = (24.5)^2 - 4*(-4.9)*(117.6) = \underline{ \ \ \ \ \ \ \ \ \ \ \ \ }\]
Fill in the blank. Tell me what you get.

Answer 12

Heres the definition of the quadratic formula :)

i think you just got confused with the +-

Btw, a little piece of advice, never forget b^2 - 4ac

Answer 13

so would t=−2.9999999999999996,8 ?

Answer 14

you should get t = -3 or t = 8

Answer 15

so it looks like you pretty much got it. You just need to round -2.9999999999999996 to -3

Answer 16

yep, t= -3 and t=8

Answer 17

oh right! I always forget to round! thank you!!

Answer 18

If t is a time value, then only t = 8 makes sense. A negative time value makes no sense.

Answer 19

okay thank you

Answer 20

Good work. Thanks for asking for me. I forgot to close my OpenStudy window last night, so didn't know to come and help!