Respuesta :

mhanifa

Answer:

2

Step-by-step explanation:

  • 2×2^2x - 7×2^x - 4=0
  • 2×(2^x)^2 - 7×2^x - 4 = 0

Substitute 2^x = y, where y>0

Then we get quadratic equation:

  • 2y^2 - 7y - 4 = 0

Solving this, we get y = 4 as positive root, so;

  • y = 4
  • 2^x = 4
  • 2^x = 2^2
  • x = 2

Answer is 2

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