-6/7
Negative six over seven
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.
(4.8*10^8)/(1.2*10^4)2.2*10^-8=11/<span>12500</span>
I hope this helps
Well first you have to simplify the denominators with x, by multiplying the denominator on the left times the top and bottom of the middle, and vice versa to get 10x/(4x^2-4x)-9(2x-2)/(4x^2-4x)=-1/4 and then you combine the fractions on the left to get 2(9-4x)/(4x^2-4x)=-1/4 and then you cross multiply the fractions to get 8(9-4x)=-4x^2+4x and then simplify to get 72-32x=-4x^2+4x and then 4x^2-36x+72=0 which then we can turn into 4(x-6)(x-3)=0 so x is 6 and 3
