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If the equations x^2+a x+b=0 and x^2+b x+a=0(a b) have a common root, then a+b is equal to

Options

  1. A-1
  2. B1
  3. C3
  4. D4

Correct answer

A. -1

Step-by-step solution

Let be the common root, then array rlrl & ^2+a +b & =0 and & ^2+b +a & =0 & & ^2 a^2-b^2 & = b-a = 1 b-a & & b-a & = 1 b-a =1 Now, & ^2 a^2-b^2 & = b-a & 1 (a+b)(a-b) & = 1 -(a-b) & a+b & =-1 array

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