Q531
If a + a2 + a3 - 1 = 0, then what is the value of a^3 + 1/a?
If a + a2 + a3 - 1 = 0, then what is the value of
A.
1
B.
4
C.
2
AnswerD.
3
Answer: Option C
Solution
Answer: Option C
Solution:
a + a2 + a3 - 1 = 0a3 = 1 - a2 - a . . . . . . . . (i)
a + a2 + a3 = 1
on dividing by a
a2 + a + 1 = . . . . . . . . (ii)
Add equation (i) & (ii),
= 1 - a2 - a + a2 + a + 1
= 2