Answer:
s₃ = 4n² - 6
Explanation:
The perimeter is the sum of the three sides. The unknown side will be a variable expression.
Perimeter = s₁ + s₂ + s₃
s₃ = Perimeter - s₁ - s₂
s₃ = (-6n² - 2) - (-8n² + 2) - (-2n² + 2)
s₃ = -6n² - 2 + 8n² - 2 + 2n² - 2
s₃ = 4n² - 6
You can check this by summing s₁, s₂, and s₃ and you should get the given perimeter as your answer.