Which of the following values of α satisfy the equation 1 + α 2 1 + 2 α 2 1 + 3 α 2 2 +…

Which of the following values of α satisfy the equation 1+α21+2α21+3α22+α22+2α22+3α23+α23+2α23+3α2= -648 α ?
  1. -4
  2. 9
  3. -9
  4. 4

Solution

1+α21+2α21+3α22+α22+2α22+3α23+α23+2α23+3α2

R2R2-R1 (Take common)
R3R3-R1

21+α21+2α21+3α23+2α3+4α3+6α4+2α4+4α4+6α

R3R3-R2

21+α21+2α21+3α23+2α3+4α3+6α111

C2C2-C1 (Take common)
C3C3-C1

2α2.α1+α22+3α2+4α3+2α22100

4α2-2α=-8α3=-648α
α=0, α2=81, α=±9

Asked in: JEE Advanced 2015 (Paper 1)

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