a) what is the variable? Ask yourself, what is being measured? what quantity are they curious about? not the volume of the sample, not the color..... it's the concentration of nitrogen. That's what they want to know the effect of........ the nitrogen in the lake causes unwanted effects.
b)...

the ordered pairs given represent the input (x) and output (y) values from the given equation.
2 x 5^1 = 10
2 x 5^2 = 50
2 x 5^3 = 250
The question is asking how much bigger does the output get at each point.
Since you're adding 1 to the exponent...

There's a lot of information in this problem, but all these kind of problems are some version of
Distance = Rate * Time
If the two riders are going to meet in the middle somewhere, we know that their combined distance covered is 12 miles. Since he left first, let's call Sam rider...

From The description in this problem, we can generate two equations:
3J + 2T = 30
T = 5J - 11
If you substitute the second one (for T) in for T in the first one, you can solve for J. Then replace the solution into either of the original equations and solve for...

Can you picture these two rods as two of the sides of a right triangle? The third side would be formed by connecting the two ends that are not at the origin. This question is asking where (the ordered pair) the centroid of that triangle would be. Since the Centroid is formed at the concurrence of...

The distance between the bounces is being cut in half each time:
16, 8, 4, 2, 1, 0.5, 0.25, 0.125, 0.0625, 0.03125, 0.015625, 0.0078125
1 2 3 4 5 6 7 8 9 ...

I had to look up the conversion factor:
1 KM = 0.62137 miles
so
4 Km = 4(0.62137) miles = 2.485 miles or about 2.5 miles deep.

14,780,000
-7,300,000
7,480,000 <<< growth in the 23 years from 1190 to 2013 (this is where they get the
"approximately double in 23 years"
The...

It has already risen 4, so it has 8 inches to go. at 2 inches per hour this will take another 4 hours. In a number sentence we would say it like this:
4 inches + 2 in/hr * (? Hrs.) = 12
Subtract 4 from both sides:
(2 in/hr) * H = 8
H...

Always figure the % discount from the original price.
1250 - 900 = 350 << this is how much $ is subtracted to reach the new price. This is the discount.
350 is what percent of 1250?
1250(P) = 350
350/1250 = 0.28
discount...

3D + 6G = 84
12D +12G = 240
We can make this system easier by dividing through each of the equations by a common factor. In the first equation I'm going to divide everything by 3, and in the second by 12. Then I get this:
D + 2G = 28
D +...

There are two relationships described, let's write equations to match them:
9S + 2L = 110
10S + 14L = 346
Now let's solve one of these for ONE of the variables. (I'm going to chose the first one because it has smaller numbers)
1.) move the...

30 posts per 24 hours elapsed time.
30/24 = 1.25 posts per hour is your rate.

I think, maybe, what they're asking for is the following:
let T = temperature.
temperatures higher (warmer) than -8 would be T > -8C
temperatures lower (colder) than -8 would be T < -8C
Is there more information given in the question...

Hi Marie -
The process of completing the square is pretty simple: Start by moving the constant term to the other side of the equals sign by adding 3 to both sides. Then we have this:
x2 + 2x + ___ = 3
Now divide the coefficient on the x term...

In general:
Total purchase price = sticker price + (sticker price)*(tax rate as a percent)
In this problem:
5.28 = P + (P)*(.10)
Think of the right hand side of this equation as...

x....3.5 ft........x.........3.5 ft........x..... etc......
Post post post
First this question is asking how many sections 3.5 feet long fit in a fence 210...

His trip looks something like this:
Home.......Ball Field........ School
|< 2miles >|< x miles >|
|< 6 miles ...

Riders' height = R
This is a problem that is examining the translation of the words "at least" into an inequality sign. We know that this kind of limitation is meant to exclude people that are shorter than 48 inches tall right? So let's write this:
R...

Time "lapse" is the same as "time difference", right?
When we use the word difference in math we need to subtract:
9:29
- 6:32
since the minutes in the bottom number are bigger than the ones in the upper number
we...