Question

anyone in algebra 1b?quadric functions and equations unit test

Answer 1

Hello and Welcome to OpenStudy! :)

Most prospective tutors and I would be more inclined to answer you quickly if you'd please post your homework problem immediately. then anyone willing to help you will help you.

Answer 2

ok i have 2 questions

Answer 3

A model rocket is launched from a roof into a large field.The apth of the rocket can be modeled by the equation y=-0.04x^2 + 8.3x + 4.3,where x is the horizontal distance in meters,from the starting point on the roof and y is the height in meters,of the rocket above the ground.How far horizontally from the starting point will the rocket land?Round your answer to the nearest hundredth meter.

Options are
A. 208.2 m
B 416.03 m
C.0.52 m
D.208.19 m

Answer 4

Landon is standing in a hole that is 6.5 ft deep. He throws a rock, and it goes up into the air, out of the hole, and then lands on the ground above. The path of the rock can be modeled by the equation
y = –0.005x² + 0.45x – 6.5, where x is the horizontal distance of the rock, in meters, from Landon, and y is the height, in meters, of the rock above the ground. How far horizontally from Landon will the rock land?
18.07 ft
35.96 ft
9.04 ft
71.93 ft

Answer 5

where the rocket will land would be when height = y = 0
so solve for x when 0 = -0.04x^2 + 8.3x + 4.3

Answer 6

How do i solve for x?im really bad at this

Answer 7

I suppose you would use the quadratic formula, have you learned that? :)

Answer 8

No I get it mixed up/:

Answer 9

\[\large quadratic~formula = \frac{ -b \pm \sqrt{b^2 - 4ac} }{ 2a }\]when in form ax^2 + bx + c = 0

so plug in a = -0.04
b = 8.3
and c = 4.3

Answer 10

im still confused what do i do after i plug it in

Answer 11

\[\frac{ -8.3 + \sqrt{8.3^2 - (4*-0.04 * 4.3)} }{ 2* -0.04 }\]

Answer 12

I'm guessing you're allowed to use a calculator?

Answer 13

okay I would solve this but I dont have my calculator

Answer 14

http://www.wolframalpha.com/input/?i=0%3D-0.04x%5E2+%2B+8.3x+%2B+4.3

Answer 15

it would be the positive one

Answer 16

Oh thank you so much

Answer 17

so its d then?

Answer 18

yep :)

Answer 19

(now to copy paste so I don't have to scroll XD)

Landon is standing in a hole that is 6.5 ft deep. He throws a rock, and it goes up into the air, out of the hole, and then lands on the ground above. The path of the rock can be modeled by the equation
y = –0.005x² + 0.45x – 6.5, where x is the horizontal distance of the rock, in meters, from Landon, and y is the height, in meters, of the rock above the ground. How far horizontally from Landon will the rock land?
18.07 ft
35.96 ft
9.04 ft
71.93 ft

Answer 20

its just 0.05x^2 with 2 zeros(:

Answer 21

negative

Answer 22

so 0.05 not 0.005 ?

Answer 23

yeah -0.05^2

Answer 24

-0.05x^2*

Answer 25

are you sure??? :/
the -0.005x^2 had an answer
-0.05x^2 doesn't have an answer...

Answer 26

Yeah im sure whats the answer though?Is it any of the choices

Answer 27

ah yes it would be -0.005x^2

you would use the same idea
and use logic to know that out of the two answers you could get, the right one would be when the line comes back down and hits the ground...
http://www.wolframalpha.com/input/?i=0+%3D+%E2%80%930.005x%C2%B2+%2B+0.45x+%E2%80%93+6.5

Answer 28

So its D then

Answer 29

yes :)

but do you understand the idea behind plugging into the quadratic formula?

Answer 30

Yup I just didn't remember the formula thanks alot though

Answer 31

glad I could help :)