Science & Mathematics - 11 December 2007

27 cm is the length

2007-12-11 03:59:03 · 4 answers · asked by Anonymous in Mathematics

Heres a typical example:

3x+2y=4
5x-2y=18

And

2x+3y=2
8x+3y=17


And

3x-4y=6
5x-4y=2


I dont want to know how to solve them, all I need to know is how do you know weather to + or minus the numbers? like in the last example I know you cancell the 4y to become 0 but what about the 3x and 5x does that minus to? ( + and + = - )

Thanks for the help

2007-12-11 03:57:37 · 4 answers · asked by Anonymous in Mathematics

2007-12-11 03:57:08 · 10 answers · asked by Anonymous in Mathematics

I want to know can it be done?

2007-12-11 03:56:24 · 17 answers · asked by Tom Thumb 1 in Astronomy & Space

2007-12-11 03:55:21 · 6 answers · asked by aaronluevanos 1 in Mathematics

√26

a. 13
b. 13√2
c. 2√13
d. √26

2007-12-11 03:53:57 · 2 answers · asked by . 1 in Mathematics

2007-12-11 03:50:37 · 6 answers · asked by Anonymous in Astronomy & Space

When I draw a triangle and then enlarge it with a scale of what ever : How can I find the centre of enlargement of those 2 Triangles ? Thank you

2007-12-11 03:50:11 · 2 answers · asked by Anonymous in Mathematics

I understand the initial process being thermal decomposition changing the compound into copper oxide. I would relish in the knowledge of how to then change this into copper. Please help. Thank you.

2007-12-11 03:47:44 · 3 answers · asked by Anonymous in Chemistry

A steam engine has a boiler that operates at 500K. The energy from the boiler changes water to steam, which drives the piston. THe temperature of the exhaust is that of the outside air, 300K. You may assume an ideal engine.
a) what is the engine's efficiency?
b) If 3.5E3 J of energy is delivered to the engine (QH) during one cycle, find the work done by the engine.

2007-12-11 03:42:40 · 1 answers · asked by rachhar123 1 in Physics

A. denitrification
B. deammonification
C. nitrogen fixation
D. ammonification
E. production of amino acids

2007-12-11 03:40:17 · 3 answers · asked by Anonymous in Biology

A system of monatomic ideal gas starts at a pressure of 1.0E5 Pa, a volume of 5.0E-3m and an initial temperature of 300K. Gas is confined to cylinder by a movable piston. Gas slowly expands at constant volume to pressure of 3.0E5Pa. This is point B. Next it undergoes an isothermal compression to point C. At point C the pressure is 1.0E5Pa. Finally gas is compressed isobarically until it returns to its original conditions of temperature, pressure and volume.
a) Draw the PV diagram
b) find the # of moles of gas
c) Find the Temperature at B
d) Find the change in internal energy (U), Q & W (work) for isobaric process
e) find the change in U, Q &W for isochoric process
f) find net change in internal energy for entire cycle
g) Is work done on or by the gas? Explain

2007-12-11 03:40:16 · 2 answers · asked by rachhar123 1 in Physics

THIS IS HOW THE PROBLEM ACTUALLY IS PLACED....... 4X+Y=-2. and below it is... 4X+3Y=-12 how is it that i can go about solving it and get the right answer?thanks MC

2007-12-11 03:38:22 · 2 answers · asked by Michelle C 1 in Mathematics

THIS IS HOW THE PROBLEM ACTUALLY IS PLACED....... 4X+Y=-2. and below it is... 4X+3Y=-12 how is it that i can go about solving it and get the right answer?thanks MC

2007-12-11 03:36:35 · 6 answers · asked by Michelle C 1 in Mathematics

When is the next waning moon phase in December 2007?

2007-12-11 03:35:21 · 3 answers · asked by Anonymous in Astronomy & Space

THIS IS HOW THE PROBLEM ACTUALLY IS PLACED....... 4X+Y=-2........................................................................................ 4X+3Y=-12 how is it that i can go about solving it andget the right answer?thanks MC

2007-12-11 03:35:03 · 4 answers · asked by Michelle C 1 in Mathematics

how do I draw a triangle with certain different measurements using a protractor??

2007-12-11 03:31:55 · 1 answers · asked by B-rock 2 in Mathematics

2007-12-11 03:28:46 · 3 answers · asked by muhsi36 1 in Mathematics

a drilling rig 12 miles offshore is to be conneced by a pipe to a refinery onshore, 20 miles down the coast from the rig. If underwater pope costs $50,000 per mile and land-based pipe costs $30,000 per mile, what values of x and y give the least expensive connection?

2007-12-11 03:28:03 · 1 answers · asked by Frank da Tank 1 in Engineering

2007-12-11 03:26:49 · 2 answers · asked by h 1 in Mathematics

So I live in Michigan so this can only be a northern species. It has a longer looking body, but its still not big. It also has a short tail. (about an inch) And its grey. The face looks completly diffrent than a mouse. (small eyes, longer muzzle)

Does anyone know what this could be and?!?!

2007-12-11 03:26:12 · 23 answers · asked by Stacey 2 in Zoology

2007-12-11 03:25:44 · 1 answers · asked by airplane68 1 in Biology

1⁄2 kg Flour
20 g yeast
50 g sugar
1⁄4 l milk
2 eggs
50 g butter

2007-12-11 03:24:12 · 3 answers · asked by Learning is fun! 4 in Mathematics

I'm having difficulting understanding the concept of inverse
and i dont know what inverse pairs undo each other means?

2007-12-11 03:21:37 · 2 answers · asked by Anonymous in Mathematics

CSU have just released their predictions for the 2008 hurricane season and are predicting 13 names storms, 7 hurricanes and 3 major hurricanes, do you think this this is an accurate prediction?

The long term average is 9.6 names storms per year, 5.9 hurricanes and 2.3 major hurricanes.

This time last year they made their predictions for 2007 stating they beleived there would be 14 named storms, 7 hurricanes and 3 major hurricanes. On each count they were out by just one (actual activity being 15, 6 and 2).

2007-12-11 03:16:01 · 6 answers · asked by Trevor 7 in Weather

2007-12-11 03:12:47 · 2 answers · asked by Anonymous in Biology

i need the answers for these questions for a paper. THANKS!

2007-12-11 03:11:09 · 2 answers · asked by ღ♥ツl٥ﻻﻉ√٥υ f٥rﻉ√ﻉrツ♥ღ 2 in Earth Sciences & Geology

Why do cities on the EAST side of Lake Erie (ex. Cleveland, Ashtabula) tend to get MORE snow than cities on the WEST side of the lake (ex. Toledo,)?

2007-12-11 03:10:53 · 3 answers · asked by Anonymous in Weather

you must pay $1.75 to enter a game in which a fair coin is tossed 3 times and you are paid the same number of dollars as the number of tosses that come up as Heads. What is the expected value of this game? Is it fair?

2007-12-11 03:09:10 · 3 answers · asked by Anonymous in Mathematics

http://news.yahoo.com/nphotos/NASA/photo//071211/photos_sc/2007_12_10t201557_450x322_us_space_voyager//s:/ap/20071211/ap_on_sc/solar_system_edge;_ylt=Ap6GATofIPvOWeLgtJ5gGCFxieAA

What is the yellow thing? Is the blue thing our solar system? What is the "shell" around it? Are those the two Voyager models in the picture?

2007-12-11 03:07:42 · 11 answers · asked by searching_please 6 in Astronomy & Space