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AP EAMCET · Maths · Quadratic Equation

Value of a for which equations x3+ax+1=0 and x4+ax2+1=0 have a common root

  1. A 0
  2. B 1
  3. C -2
  4. D none of these.
Verified Solution

Answer & Solution

Correct Answer

(C) -2

Step-by-step Solution

Detailed explanation

Given equations are x3+ax+1=0 ⇒x4+ax2+x=0   …1 And, x4+ax2+1=0   …2 Subtracting equations 1 and 2, we get x-1=0 ⇒x=1 Thus, x=1 is the common root. Hence, 1+a+1=0 ⇒a=-2