Multply both equations by 2 leaving
x + 2y = 8
x - 2y = -2
Add the equations giving
2x = 6
x = 3
Substitute 3 in the top equation
3 + 2y = 8
2y = -5
y = -2.5
We want to find the mean of two elements in a set, given that we know the other elements of the set and the mean of the whole set.
The answer is: -490
-----------------------------
For a set with N elements {x₁, x₂, ..., xₙ} the mean is given by:

Here we know that:
- The mean of the set is 0.
- The set has 1000 elements.
- 998 of these elements are ones, the other two are A and B.
We want to find the mean of the values of A and B.
First, we can start by writing the equation for the mean:

We can rewrite this as:

And we have 998 ones, then:

Now we have B isolated.
With this, the mean of A and B can be written as:

So we can conclude that the mean of the other two numbers is -490.
If you want to learn more, you can read:
brainly.com/question/22871228
1- Line:
A line is a one dimensional figure that is formed by joining an infinite set of points.
It has no start and no end.
Answer:
Line ..............> A) infinite number of points extending in opposite directions that has only one dimension
2- Line segment:
It is the same as the line. The only difference is that a line segment has a fixed start point and a fixed end point. It is considered to be a portion of a line
Answer:
Line segment .........> D) a part of a line that has two endpoints
3- Ray:
A ray is also a one dimensional shape. A ray usually has a start point but no end point.
Answer:
Ray .........> B) part of a line that has one endpoint and continues in one direction infinitely
4- Point:
A point is a dimensionless geometric shape. It is only used to state a certain location.
Answer:
Point .........> C) a location, has no dimension
5- Vertex:
A vertex is a term that is used to refer to the point where the two rays forming an angle meet.
Answer:
Vertex ........> E) the common endpoint of two segments or rays that form the corner of an angle
Hope this helps :)
Answer:
-4ctv² + 10xyz - 9
Step-by-step explanation:
(2 + 5xyz - 6tv²c) - (11 - 5yxz - 2ctv²)
2 + 5xyz - 6tv²c - 11 + 5yxz + 2ctv²
-4ctv² + 10xyz - 9
I hope this helps!