Answer:
The sum of first 4n terms is -10n.
Step-by-step explanation:
The formula for sum of n terms of an AP is
It is given that the sum of the first n terms of an A. P. is 2n and the sum of the first 2n terms is n.
..... (1)
..... (2)
Solve equation (1) and (2) by elimination method.
The sum of first 4n terms is
Put the value of a and d.
Therefore the sum of 4n terms is -10n.
Answer: The placebo group serves as the control group because this group corresponds to the reference point that will be compared to the other group.
Step-by-step explanation:
The control group is a reference point in an experiment they usually never receive any treatment and serves as benchmark to compare other test result which are measured. The control groups also includes individual with similar characteristics like those been tested e.g Age, health history.
Members in a control group are usually given placebos and usually do not know that they are part of the control group. This helps the researcher determine the effectiveness of the study being carried out.
Answer:
<h3>-41</h3>
Step-by-step explanation:
Given the expression written by the teacher as;
-16+(-25)
We are to find the equivalent expression.
Note that +×– = –
Hence;
-16+(-25)
= – 16 – 25
= - 41
Hence the resulting value of the expression is –41
Answer:
x = 1/5.
Step-by-step explanation:
y = k/x where k is a constant.
When y = 6, x = 2 so we have:
6 = k/2
k = 12.
So the relation is y = 12/x.
When y = 60:
60 = 12/x
6x = 12
x = 12/60
x = 1/5.
The answer to the area of the triangle is 21 because the base is equal to 6 and the height is 7 so you multiply 6 times 7 then divided by 2 because a triangle is 1 half of a square