Answer:
11x-y or 5x+y.
Step-by-step explanation: I hope this helps, I really don't know what the question means, since it not that specific.
Answer:
495 combinations of 4 students can be selected.
Step-by-step explanation:
The order of the students in the sample is not important. So we use the combinations formula to solve this question.
Combinations formula:
is the number of different combinations of x objects from a set of n elements, given by the following formula.

How many combination of random samples of 4 students can be selected?
4 from a set of 12. So

495 combinations of 4 students can be selected.
Answer:
The exponential model is
.
Step-by-step explanation:
The exponential model can be modelled by the following mathematical expression:
(1)
Where:
- Independent variable.
- Dependent variable.
- Coefficients.
If we know that
and
, then we get the following system of equations:
(2)
(3)
If we divide (3) by (2), we calculate the value of
:



And by (2), we determine the value of
:


The exponential model is
.
Let's build the equation counting how many x's and 1's are there on each side.
On the left hand side we have 5x's and 8 1's, for a total of 
On the left hand side we have 3x's and 10 1's, for a total of 
So, the equation we want to solve is

Subtract 3x from both sides:

Subtract 8 from both sides:

Divide both sides by 2:

Answer:
30 ft²
Step-by-step explanation:
The formula to find the area of a rectangle is:
Length x Width