Respuesta :

Answer:

  • None

Step-by-step explanation:

Given expression

  • 9x² - 2(k + 7)x + k

If this is a perfect square then it should be in the form of:

  • (3x)² - 2(3x)(√k) + (√k)²

Comparing the two expressions, we see that:  

  • (k + 7) = 3√k
  • (k + 7)² = 9k
  • k² + 14k + 49 - 9k = 0
  • k² + 5k + 49 = 0
  • D = √(5² -4*49) = √-171

Since the discriminant is negative, there is no solution