I'm not an expert at this but use the khan academy video on unit circle to help you tackle that problem.
B. 15 because
-18+x=-3
X= -3 + 18
X = 15
3 multipled by square root of 2 cm.
Answer:

Step-by-step explanation:
a₁ = 1 - 5(1 - 1) = 1 - 5·0 = 1
a₂ = 1 - 5(2 - 1) = 1 - 5·1 = 1 - 5 = a₁ - 5
a₃ = 1 - 5(3 - 1) = 1 - 5·2 = 1 - 5 - 5 = a₂ - 5
a₄ = 1 - 5(4 - 1) = 1 - 5·3 = 1 - 5 - 5 - 5 = a₃ - 5
and so on, therefore:
<h3>
aₙ = aₙ₋₁ - 5</h3>