Verified Solution Mathematics Polynomials

Assertion (A): If the zeros of the polynomial x² + px + q are twice the zeros of 2x² - 5x - 3, then p = 5 and q = -18. Reason (R): For a quadratic polynomial ax² + bx + c, sum of zeros = -b/a and product of zeros = c/a.

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Solution ✔ Verified
  • ABoth A and R are true and R is the correct explanation of A.
  • BBoth A and R are true but R is not the correct explanation of A.
  • CA is true but R is false.
  • DA is false but R is true.
Explanation

R is true (standard formulas). For 2x² - 5x - 3, zeros are alpha, beta. alpha+beta = 5/2, alpha*beta = -3/2. For x²+px+q, zeros are 2alpha, 2beta. Sum = 2alpha+2beta = 2(alpha+beta) = 2(5/2) = 5. So -p=5 => p=-5. Product = (2alpha)(2beta) = 4alpha*beta = 4(-3/2) = -6. So q=-6.

The assertion states p=5 and q=-18, which is incorrect as per my calculation (p=-5, q=-6). Therefore, A is false. The problem has A is true in explanation. Let me re-read the options. "A is true but R is false" / "A is false but R is true". I have derived A is false and R is true.

Let me re-check the calculation carefully to ensure there is no error on my part. Given 2x² - 5x - 3. Let its zeros be m and n. m+n = -(-5)/2 = 5/2. mn = -3/2. New polynomial is x² + px + q. Its zeros are 2m and 2n. Sum of new zeros = 2m+2n = 2(m+n) = 2(5/2) = 5. So, -p = 5 => p = -5. Product of new zeros = (2m)(2n) = 4mn = 4(-3/2) = -6. So, q = -6. Therefore, p=-5 and q=-6. Assertion (A) says p=5 and q=-18. This means Assertion A is definitely FALSE.

Reason (R) states the standard formulas, which are TRUE.

So the correct option should be "A is false but R is true". This is option D.

Let me correct my provided explanation to align with this.

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