Respuesta :

Answer:

  • k = 20

Step-by-step explanation:

Perfect square identity:

  • (a + b)² = a² + 2ab + b²

Completing the square:

  • 4x² - 32x - 20 + k =
  • (2x)² - 2*2x*8 + 8² - 20 + k =
  • (2x - 8)² - (20 - k)

In order the given to be a perfect square, we need:

  • 20 - k = 0
  • k = 20