Science & Mathematics - 22 November 2007

#1,
x/3+4y=30
2x-y=5
#2,
6x-y/4=-9
3x+2y=-30

2007-11-22 12:12:07 · 4 answers · asked by Anonymous in Mathematics

If so then what do they see? If you say black and white, aren't these colors aswell?

2007-11-22 12:11:53 · 1 answers · asked by Anonymous in Biology

im doing a science project on how does temperature affect air quality, and i said that the hotter the temperatures the worse the air quality because the hot temperatures help to form the ground- level layers of ozone. But because that ozone forms is it really making the air qualoty worse. i have been searching all over the internet, and i cant find it. im getting worried that i might have made a mistake on my project idea cause i have to be doing it all year as a long-term project. so i just wanted to know if warmer temperatures really made air quality worse. thanks for any help ! its greatly appreciated !

2007-11-22 12:09:39 · 10 answers · asked by xodanceox 2 in Weather

2007-11-22 12:08:44 · 7 answers · asked by Melissa G 1 in Mathematics

2007-11-22 12:05:25 · 2 answers · asked by Anonymous in Chemistry

2007-11-22 12:03:36 · 3 answers · asked by Salvador 2 in Chemistry

y=x^2-4
y=x-2

2007-11-22 12:01:35 · 3 answers · asked by michael s 1 in Mathematics

A light dimmer is a possible application of a series RL-circuit. Assume for simplicity that the resistance of the lightbulb is constant with R=100 Ohm. For a dimmer, the bulb is connected in series with a variable inductance L.
The circuit is connected to a wall outlet with 115V AC oscillating at 60 Hz. What range of L is needed if it is desired
to vary average power from 30W to 100W?

2007-11-22 12:00:28 · 2 answers · asked by Ali Ahmed 2 in Engineering

of the 100 counties in North Carolina.

2007-11-22 11:56:47 · 2 answers · asked by Lisa V 1 in Geography

0 <= theta < 2pi

Could someone please explain how to solve these problems? Thanks.

1. 4 cos^2 theta - 3 = 0

2. cos^2 theta - sin^2 theta + sin theta = 0

2007-11-22 11:56:26 · 4 answers · asked by labelapark 6 in Mathematics

2007-11-22 11:55:29 · 9 answers · asked by Jake A 1 in Astronomy & Space

(1/2)(sin x)[(sin x)/(1-cos x) + (1-cos x)/(sin x)] = 1

2007-11-22 11:54:35 · 3 answers · asked by max 2 in Mathematics

2007-11-22 11:50:13 · 11 answers · asked by Anonymous in Geography

2007-11-22 11:49:39 · 16 answers · asked by Mike M. 7 in Weather

2007-11-22 11:45:41 · 2 answers · asked by Connie H 1 in Chemistry

Can someone please tell me the mass % of Copper(I)Sulfide and Copper(II)Sulfide? Please explain how you got your answer.

2007-11-22 11:43:28 · 2 answers · asked by lovebug 2 in Chemistry

Tima has reduced his cholesterol level by 20% by dieting and exercising. If his original level was 238, what is his new cholesterol level?

2007-11-22 11:34:02 · 11 answers · asked by Anonymous in Mathematics

2007-11-22 11:31:12 · 4 answers · asked by Anonymous in Weather

Hey guys, I have a few questions for a lab report I'm doing, any help or answers to any or all questions would be really appreciated:

What is the scientific name for vinegar?

What is the chemical formula for binegar?

What type of compound is vinegar?

What is the scientific name for the active ingredient in Alka-Seltzer?

What is the chemical formula for the active ingredient in Alka-Seltzer?

What type of compound is the active ingredient in Alka-Seltzer?

What is the equation for the reaction being observed? (balanced equation would be best)

What type of reaction is taking place?


All your help is really greatly appreciated, I'll be doing my own research on these questions and waiting for your responses, thanks guys.

2007-11-22 11:23:54 · 2 answers · asked by Anonymous in Chemistry

How accurate is it?

2007-11-22 11:20:47 · 2 answers · asked by H I 1 in Physics

I heard osmething baout using PVC pipe to make a flute. but the PVC has to be plastic or something.

can anyone tell me mroe baout this in simplet terms?

2007-11-22 11:18:54 · 3 answers · asked by Anonymous in Engineering

C2H4Cl2 + O2 => CO2 +H2O +HCl


I know that I start like this...
C2H4Cl2 + O2 => 2CO2 + H2O + HCl

but how do you know where to go from there?
also how do you know when to double your results?
Please inform me on how to do these type of problems thank you

2007-11-22 11:17:24 · 1 answers · asked by Anonymous in Chemistry

We have to consider their feelings....

Love Jack

2007-11-22 11:12:15 · 10 answers · asked by Jack 5 in Biology

apart from USA, as it obviously isn't..

2007-11-22 11:10:20 · 21 answers · asked by Olly S 2 in Geography

1) Two numbers hav a sum of 60. find the numbers if their product is a maxium.

2) A rectangular lot is bordered on one side by a stream and on the other 3 sides by 600m. of fencing, find the dimensions of the lot if its area is a maxium.


THXXX SOOOOO MUCH!!!!!! FOR ANSWERING!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! =]

2007-11-22 11:09:39 · 2 answers · asked by Cresentia S 3 in Mathematics

Solve using simultaneous equations:

Flour is sold in packets of 5kg and 2kg. The 5kg packets cost $2.75 each and the 2kg packets cost $1.25 each. If I bought 67kg of flour and the total cost was $38.50, how many of each kind of packet did I buy?

Full working out would be so appreciated :)

2007-11-22 11:06:43 · 4 answers · asked by Anonymous in Mathematics

can someone tell me the hex values to 10
20
30
40
50
60
70
80
90 and
100?

2007-11-22 11:04:26 · 4 answers · asked by Andres 1 in Mathematics

we directly experience 4 dimensions - 'up/down', 'in/out', 'side-to-side' and time, right?
how come we only experience the last one as being 'uni-directional'...if i understand it right then mathematically there's no reason for this?(i mean that time only goes one way for us,PLEASE put me right if i ain't!)...

my THOUGHT was that time was the dimension that we experience the other three 'in', as it were and that if we were in a fifth dimension that 'contained' space/time then we would be able to move back and forwards in time as easily as i can move up and down etc. is that right?

if so - how come the dimension at the top of my hierarch is directional? if we could experience a fifth dimension would THAT be one-directional like time is for us now? and - this is the important bit for me - WHYYY!!!????

any elucidating concepts would be appreciated, ty.

2007-11-22 11:01:13 · 7 answers · asked by mlsgeorge 4 in Physics

A golf company has determined that the daily per unit cost C of manufacturing x additional Big Bertha – type golf clubs may be expressed by the quadratic function

C(x) = 5x^2 – 620x + 20,000

a)How many clubs should be manufactured to minimize the additional cost per club?

b)At this level of production , what is the additional cost per club?

2007-11-22 10:53:35 · 5 answers · asked by Anonymous in Mathematics

Express your answer in scientific notation.

I know it's something like pH= -log [H+], but I cannot figure it out for the life of me.

2007-11-22 10:53:08 · 1 answers · asked by ms_lotr_freak 3 in Chemistry