Verified Solution Mathematics Quadratic Equations

The roots of the equation x² - (k+1)x + (k+4) = 0 are real and equal. Find the value of k.

10 views 4 helpful Updated Jul 14, 2026
Solution ✔ Verified
  • A0 or 1
  • B2 or 3
  • C5 or -3
  • D-1 or 3
Explanation

For real and equal roots, the discriminant D must be 0. D = [-(k+1)]² - 4(1)(k+4) = 0. This expands to k² + 2k + 1 - 4k - 16 = 0. This simplifies to k² - 2k - 15 = 0. Factoring gives (k-5)(k+3) = 0. Therefore, k=5 or k=-3.

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