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AP EAMCET · Maths · Quadratic Equation

If a is a positive integer such that the roots of the equation 7x2-13x+a=0 are rational numbers, then the smallest possible value of a is

  1. A 5
  2. B 6
  3. C 7
  4. D 8
Verified Solution

Answer & Solution

Correct Answer

(B) 6

Step-by-step Solution

Detailed explanation

Given, 7x2-13x+a=0 For rational roots D≥0 and D must be perfect square. ⇒169-28a≥0 Now, we see from options that a=7 & a=8 are not possible as then D<0. For a=5, D=168-28×5=29≥0 But it is not perfect square. For a=6,…