Given:
First term of an arithmetic sequence is 2.
Sum of first 15 terms = 292.5
To find:
The common difference.
Solution:
We have,
First term: 
Sum of first 15 terms: 
The formula of sum of first n terms of an AP is
![S_n=\dfrac{n}{2}[2a+(n-1)d]](https://tex.z-dn.net/?f=S_n%3D%5Cdfrac%7Bn%7D%7B2%7D%5B2a%2B%28n-1%29d%5D)
Where, a is first term and d is common difference.
Putting
, n=15 and a=2 in the above formula, we get
![292.5=\dfrac{15}{2}[2(2)+(15-1)d]](https://tex.z-dn.net/?f=292.5%3D%5Cdfrac%7B15%7D%7B2%7D%5B2%282%29%2B%2815-1%29d%5D)
![292.5=\dfrac{15}{2}[4+14d]](https://tex.z-dn.net/?f=292.5%3D%5Cdfrac%7B15%7D%7B2%7D%5B4%2B14d%5D)
![292.5=15[2+7d]](https://tex.z-dn.net/?f=292.5%3D15%5B2%2B7d%5D)
Divide both sides by 15.




Dividing both sides by 7, we get


Therefore, the common difference is 2.5.
Subtract
from both sides to get



Answer:
False?
Step-by-step explanation:
I'm pretty sure it's false because wouldn't it simplify to 5y? Sorry if I'm wrong. :)
Tough sorry wish I could help u can’t too hard but I think it is equivalent to the other triangle so I think it’s 31? I THINK
Answer:
-49
Step-by-step explanation:
rule of thumb: whenever you have two negatives, they equal a positive! when you have one negative and one positive, it is a negative!
- let's start by going from left to right :))
- -24 -(-6) + (-31)
- -(-6) is actually + 6!
- -24 + 6 + (-31)
- +(-31) would be -31 because one - and one + is a -
- -24 + 6 - 31
- -18 - 31
- -49
comment or message me if you are still confused or have a question!