Sum of geometric sequence
for the sum where the initial value is a₁ and the common ratio is r and the term is n
![S_n= \frac{a_1(1-r^n)}{1-r}](https://tex.z-dn.net/?f=S_n%3D%20%5Cfrac%7Ba_1%281-r%5En%29%7D%7B1-r%7D%20)
common ratio is -3
-5 times -3 is 15, -15 times -3=-45 etc
first term is -5
and we want the 8th term
![S_8= \frac{-5(1-(-3)^8)}{1-(-3)}](https://tex.z-dn.net/?f=S_8%3D%20%5Cfrac%7B-5%281-%28-3%29%5E8%29%7D%7B1-%28-3%29%7D%20)
![S_8= \frac{-5(1-6561)}{1+3}](https://tex.z-dn.net/?f=S_8%3D%20%5Cfrac%7B-5%281-6561%29%7D%7B1%2B3%7D%20)
![S_8= \frac{-5(-6560)}{4}](https://tex.z-dn.net/?f=S_8%3D%20%5Cfrac%7B-5%28-6560%29%7D%7B4%7D%20)
![S_8= \frac{32800}{4}](https://tex.z-dn.net/?f=S_8%3D%20%5Cfrac%7B32800%7D%7B4%7D%20)
![S_8= 8200](https://tex.z-dn.net/?f=S_8%3D%208200)
the sum is 8200
Answer:
I'm assuming we need to find the number of minute she as used. to do that we can right an inequality with m being the number of minutes
18+0.06m≥88.56
we then just solve this like we would with any other algebra equation, First we subtract 18 from both sides.
0.06m≥70.56
Then we dives by 0.06
m≥1176
Rania has used at least 1176 minutes
Area of shaded region = Area of larger circle - Area of smaller circle.
We know, Area of a Circle = πr²
So, A = πr₁² - πr₂²
A = π (r₁² - r₂²)
A = π(10.2² - 5.4²)
A = 3.14 (104.04 - 29.16)
A = 3.14 (74.88)
A = 235.12
In short, Your Answer would be 235.12 cm²
Hope this helps!
Total Area = 2( 32 x 79) + (26 x 42) = 6148 m²
Number of 4 m² = 6148 ÷ 4 = 1537
Answer: The zoo can have 1537 plants.
Answer:
x=3
Step-by-step explanation:
cross multiply
5(x+3)=3(x+7)
5x+15=3x+21
5x+15-3x=3x+21-3x
2x+15=21
2x+15-15=21-15
2x=6
x=3