@Nnesha

- shaleiah

@Nnesha

- Stacey Warren - Expert brainly.com

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- katieb

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- shaleiah

Please help walk me through this.

- Nnesha

alright ready! :PD

- Nnesha

|dw:1443039690740:dw|

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## More answers

- Nnesha

for the first part
we need to find max in other words vertex point |dw:1443039751009:dw|

- Nnesha

so use the formula to find c-coordinate of the vertex \[\huge\rm x=\frac{ -b }{ 2a }\]
b=middle term
a=leading coefficient

- Nnesha

hmm 407 ??

- shaleiah

Wait...

- shaleiah

\[\frac{ 0.658 }{ 2(0.00407) }\]

- Nnesha

don't forget the sign okay \[\frac{ -0.658 }{ 2(-0.00407) }\] now solve

- shaleiah

80.83538084

- Nnesha

something wrong i didn't get that o.O

- shaleiah

I typed it in my ti-84 calculator, that's what I got..

- Nnesha

try again put the parentheses

- Nnesha

that's how you should type in ti 84
-(.658)/(2(-.000407))

- shaleiah

\[-(\frac{ .658 }{ 2(-.000407) }= 808.3538084\]

- Nnesha

yes right now
that's x coordinate of vertex now substitute x for 808 to find y-coordinate into the original equation

- IrishBoy123

|dw:1443040813328:dw|

- Nnesha

what ?? o.O

- Nnesha

hmm i mean
\[y=-.000407x^2+.658x\] in this equation replace x with 808

- shaleiah

265.948352

- Nnesha

yes right we can round it so it would be 266 that would be the height

- Nnesha

now for the 2nd part you need to find x-intercept(zeros ) of that quadratic equation

- Nnesha

i'll like to use quadratic formula bec there are negative numbers

- shaleiah

I'm not good at quadratic formulas:(

- Nnesha

\[\huge\rm \frac{ -b \pm \sqrt{b^2-4ac} }{ 2a }\]
quadratic formula
a= leading coefficient
b=middle term
c=constant so justplugin

- Nnesha

\[\huge\rm Ax^2+Bx+C\] quadratic equation
a= leading coefficient
b=middle term
c=constant

- shaleiah

\[\frac{ -.658 +\sqrt{.658^{2}-4(.00407)}}{ 2(266) }\]

- Nnesha

don't forget the C which is 0 so 4ac would be 4(.000407)(0)
and why did you replace a with 266 ?

- Nnesha

the denominator is 2a so 2(????)

- shaleiah

2(.000407)

- Nnesha

yes right \[\frac{ -.658 +\sqrt{(.658)^{2}-4(.00407)(0)}}{ 2(.000407) }\] now oslve

- Nnesha

solve**

- shaleiah

- Nnesha

please show you u got that
that's not right you should get 2 solutions

- shaleiah

I typed the equation directly in my ti-84 calculator

- shaleiah

Do i solve them seperately?

- Nnesha

hmm that wouldn't work how would you right plus minus sign in the calculator yes right solve the numerator the square root part

- shaleiah

1.316

- shaleiah

or .658?

- Nnesha

both are wrong
first solve square root \[\frac{ -.658 +\sqrt{\color{ReD}{(.658)^{2}-4(.00407)(0)}}}{ 2(.000407) }\] now just type the red part into the calculator

- shaleiah

.432964

- Nnesha

i just realized i'm the one who typed incorrectly
sorry it's plus/minus
\[\frac{ -.658 \pm \sqrt{\color{ReD}{(.43296)}}}{ 2(.000407) }\]

- Nnesha

take the square root of .43296

- shaleiah

oops

- Nnesha

right so \[\huge\rm \frac{ -.658+6.58 }{ 2(-.000407) } and \frac{ -.658-.658 }{ 2(-.000407) }\] now we can seprate plus and minus sign
and i found another typo a=negative .000407

- shaleiah

.6579969605

- Nnesha

that is same as .658
remember the number after 7 is greater than 5 so you can round it

- Nnesha

this post is solaggy

- shaleiah

yeah, lots of lag :(

- Nnesha

\[\huge\rm \frac{ -.658+6.58 }{ 2(-.000407) } and \frac{ -.658-.658 }{ 2(-.000407) }\] alright work on this brb

- shaleiah

Alright. I got 807545.4545

- shaleiah

808

- Nnesha

there are two fraction
what did you get for first one what did you get for 2nd one

- Nnesha

that doesn't looks right

- Nnesha

use parenttheses

- shaleiah

:c

- Nnesha

what ?

- shaleiah

are you sure the equation is set up correctly?

- Nnesha

\[\huge\rm \frac{ -.658+6.58 }{ 2(-.000407) } and \frac{ -.658-.658 }{ 2(-.000407) }\] yes this one is 100% correct

- shaleiah

The first fraction is: -7275...
The second fraction is: -807545

- Nnesha

ugh first fraction is .658 -.658 not (6.58)
2nd fraction is 100% right but no ur answer is not right for 2nd one

- Nnesha

tell me what did you type into the calculator for first fraction

- shaleiah

The 6.58 was the error :(

- Nnesha

\[\huge\rm \frac{ -.658+.658 }{ 2(-.000407) } \] first one

- shaleiah

0

- Nnesha

right what about other one

- Nnesha

hmm not correct what did you type into the caluclator ?

- shaleiah

I'm sorry :/
I see the error. I re typed it and I got 1616.707617

- Nnesha

yes that's right

- shaleiah

Did we finish all the steps?

- Nnesha

yep that's for 2nd part!

- Nnesha

2nd one is `how long` so it would be 1616.71
0 wouldn't be the answer

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