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# Write an ordered pair such that the y-coordinate is in terms of x for the set of points.

This is the whole question:
Given: (0, 0), (1, 2), (2, 4), (3, 6), (4, 8).
Write an ordered pair such that the y-coordinate is in terms of x for the set of points listed.

-What is an ordered pair? :(

### 3 Answers by Expert Tutors

Vivian L. | Microsoft Word/Excel/Outlook, essay composition, math; I LOVE TO TEACHMicrosoft Word/Excel/Outlook, essay comp...
3.0 3.0 (1 lesson ratings) (1)
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Hi Abaline;
(0, 0), (1, 2), (2, 4), (3, 6), (4, 8).
I think you are looking for the equation.
Let's begin with the change of y...
0,2,4,6,8
change of y is 2.
Change of x...
0,1,2,3,4
change of x is 1.
Next...At what point is the y-intercept, the value of y when x=0?
It is (0,0)
The slope-intercept equation is...
y=mx+b
m is the slope, the change of y divided by the change of x.
b is the y-intercept.
y=[(2/1)x]+0
y=2x
The standard equation is...
Ax+By=C, neither A nor B equal zero and A is greater than zero.
y=2x
Let's subtract 2x from both sides...
-2x+y=0
A must be greater than zero.  It is -2.  Therefore, we will multiply both sides by -1...
2x-y=0

I HOPE THIS HELPS!

Thanks Vivian, but what if you don't have the (0,0) coordinates in the order pairs provided?  what if the ordered pairs are only (1,1) (2,3) (3,5) (4,7)?  My daughter's teacher says "you just look at it and figure it out."  This hardly seems like a way to do math.
Kevin F. | Computer Programming and Mathematics TutorComputer Programming and Mathematics Tut...
5.0 5.0 (3 lesson ratings) (3)
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An ordered pair is a set of numbers, separated by a comma, and enclosed in parentheses. For example:

(2,3)

This is the general form used to locate points on the Cartesian coordinate system. The first number represents the x-value, and the second number represents the y-value.

For the series of points given in the problem, they want to know how to express any point in terms of x and y, so the answer is:

(x, x * 2)

In other words, for any value of x, the corresponding y-value is twice the x-value. Looking at the first two ordered pairs (or points on the Cartesian coordinate system):

(0,0) - The x-value is 0. 0 * 2 is 0, so y value is 0, which is x * 2.
(1,2) - The x-value is 1. 1 * 2 is 2, and indeed the y-value is 2.
Christopher D. | Mathematician and ProgrammerMathematician and Programmer
4.9 4.9 (299 lesson ratings) (299)
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In math (or specifically set theory) a "pair" is two numbers (or more generally elements.) An ordered pair is when the order of those two numbers matters, i.e. if (2, 3) is not the same as (3, 2) you have "ordered" pairs. In this context "ordered pair" and "coordinate" mean the same thing.

(0, 0); (1, 2); (2, 4); ... all these coordinates are ordered pairs.
[Hint hint:] but something like (x, y) or (x, 3x + 2) would also be a coordinate or ordered pair.