Answer:
a = 3, b = 1, c = - 3
Step-by-step explanation:
Substitute n = 1, 2, 3 into the n th term
a + b + c = 1 → (1)
4a + 2b + c = 11 → (2)
9a + 3b + c = 27 → (3)
Subtract (1) from (2) term by term to eliminate c
Subtract (2) from (3) term by term to eliminate c
3a + b = 10 → (4)
5a + b = 16 → (5)
Subtract (4) from (5) term by term to eliminate b
2a = 6 ( divide both sides by 2 )
a = 3
Substitute a = 3 into (4) and evaluate for b
3(3) + b = 10
9 + b = 10 ( subtract 9 from both sides )
b = 1
Substitute a = 3, b = 1 into (1) and evaluate for c
3 + 1 + c = 1
4 + c = 1 ( subtract 4 from both sides )
c = - 3
Then a = 3, b = 1 and c = - 3
