I think the answer is a scalene triangle
Answer:
a₁ = -21 (Given)
a₂ = -28
a₃ = -35
a₄ = -42
Step-by-step explanation:
First term a₁ = -21 (Given)
…………………………………
Second term a₂ :
a₂ = 
…………………………………
Third term a₃ :
a₃ = 
…………………………………
Fourth term a₄ :
a₄ = 
Answer:
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