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Question: Answered & Verified by Expert
If α,βR are such that 1-2i (here i2=-1) is a root of z2+αz+β=0, then α-β is equal to:
MathematicsQuadratic EquationJEE MainJEE Main 2021 (25 Feb Shift 2)
Options:
  • A -7
  • B 7
  • C -3
  • D 3
Solution:
2923 Upvotes Verified Answer
The correct answer is: -7

α,βR other root is 1+2i

α=-( sum of roots )=-1-2i+1+2i=-2

β=product of roots =1-2i1+2i=5

α-β=-7

option 1

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