Step-by-step explanation:
x=3.2 or if u round-up 3.3
Just a guess but I think it’s Option A
Answer: (B) -625
<u>Step-by-step explanation:</u>
Given the sequence {-500, -100, -20, -4, -0.8, ... }, we know that that the first term (a) is -500 and the ratio (r) is ![\dfrac{-100}{-500}=\dfrac{1}{5}](https://tex.z-dn.net/?f=%5Cdfrac%7B-100%7D%7B-500%7D%3D%5Cdfrac%7B1%7D%7B5%7D)
Input those values into the Sum formula:
![S_n=\dfrac{a(1-r^n)}{1-r}\\\\S_8=\dfrac{-500\bigg(1-\dfrac{1}{5}^n\bigg)}{1-\dfrac{1}{5}}\\\\.\quad=\dfrac{-500\bigg(1-\dfrac{1}{390,625}\bigg)}{\dfrac{4}{5}}\\\\.\quad=\dfrac{-500\bigg(\dfrac{390,624}{390,625}\bigg)}{\dfrac{4}{5}}\\\\.\quad=\dfrac{5(-500)(390,624)}{4(390,625)}\\\\.\quad=-624.998\\\\.\quad=-625\quad \text{(rounded to 2 decimal places)}](https://tex.z-dn.net/?f=S_n%3D%5Cdfrac%7Ba%281-r%5En%29%7D%7B1-r%7D%5C%5C%5C%5CS_8%3D%5Cdfrac%7B-500%5Cbigg%281-%5Cdfrac%7B1%7D%7B5%7D%5En%5Cbigg%29%7D%7B1-%5Cdfrac%7B1%7D%7B5%7D%7D%5C%5C%5C%5C.%5Cquad%3D%5Cdfrac%7B-500%5Cbigg%281-%5Cdfrac%7B1%7D%7B390%2C625%7D%5Cbigg%29%7D%7B%5Cdfrac%7B4%7D%7B5%7D%7D%5C%5C%5C%5C.%5Cquad%3D%5Cdfrac%7B-500%5Cbigg%28%5Cdfrac%7B390%2C624%7D%7B390%2C625%7D%5Cbigg%29%7D%7B%5Cdfrac%7B4%7D%7B5%7D%7D%5C%5C%5C%5C.%5Cquad%3D%5Cdfrac%7B5%28-500%29%28390%2C624%29%7D%7B4%28390%2C625%29%7D%5C%5C%5C%5C.%5Cquad%3D-624.998%5C%5C%5C%5C.%5Cquad%3D-625%5Cquad%20%5Ctext%7B%28rounded%20to%202%20decimal%20places%29%7D)
I guess that means adding 1.8 to both sides so it's :
t = -2.3 + 1.8