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Given that 4x^2-32x-20+k is a perfect square find k​
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Given that 4x^2-32x-20+k is a perfect square find k​

User Zholen
by
8.2k points

1 Answer

5 votes

Answer:

  • k = 20

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

User Kiet Tran
by
8.0k points
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