The original functions are: f(n) = 500 and g(n) = [9/10]^(n-1)
A geometric sequence combining them is: An = f(n)*g(n) = 500*[9/10]^(n-1):
Some terms are:
A1= 500
A2 = 500*[9/10]
A3 = 500*[9/10]^2
A4 = 500*[9/10]^3
....
A11 = 500*[9/10]^10 ≈ 174.339
Answer: the third option, An = 500[9/10]^(n-1); A11 = 174.339
3x + 1y = ¹/₃ ⇒ 9x + 3y = 1
2x - 3y = 2²/₃ ⇒ 2x - 3y = 2²/₃
11x = 3²/₃
11 11
x = ¹/₃
3x + y = ¹/₃
3(¹/₃) + y = ¹/₃
1 + y = ¹/₃
- 1 - 1
y = ⁻²/₃
(x, y) = (¹/₃, ⁻²/₃)
What do you need? I know many mathematical skills
