Answer:
f(x) = -5/9 x + 5 1/9
Step-by-step explanation:
f(2)=4 and f(−7)=9 means the line pass through (2,4) and (- 7,9)
f(x) = mx + b
m = (y-y') / (x-x') = (9 - 4) / (- 7 - 2) = - 5/9
for (2,4) : b = f(x) - mx = y - mx = 4 - (- 5/9) x 2 = 4 + 10/9 = 46/9 = 5 1/9
f(x) = -5/9 x + 5 1/9
check for (-7, 9) f(-7) = (-5/9) * (-7) + 5 1/9 = 35/9 + 46/9 = 81/9 = 9
First you have to find the angle B (check attachment)

Then you can find the last angle inside the triangle, which I'll call C

Now you can find angle A

40x - 24 - 33x - 77 = 102
40x - 33x = 102 + 24 + 77
7x = 203
x = 29
A₀ = 18 000(1 + 0.0025)⁰
A₁ = 18 000(1 + 0.0025)¹
A₂ = 18 000(1 + 0.0025)²
A(n) = 18 000(1 + 0.0025)ⁿ
So, after 5 months, A(n) = 18 000(1 + 0.0025)⁵ = $18 226.1278 ≈ 18 226.13
5 years is 60 months.
A₆₀ = 18 000(1 + 0.0025)⁶⁰ = $20 909.1021 ≈ $20 909.10