Respuesta :

mhanifa

Answer:

  • 1 cm

Step-by-step explanation:

Sides of the picture added margin:

  • l = 8 + 2x
  • w = 5 + 2x
  • A(margin) = 30 cm²

Solution:

  • A(margin) = Total area - A(picture)
  • (8 + 2x)(5 + 2x) - 5*8 = 30
  • 4x² + 10x + 16x + 40 - 40 - 30 = 0
  • 4x² + 26x - 30 = 0
  • 2x² + 13x - 15 = 0
  • x = (-13 + √(13² + 2*4*15))/4
  • x = (-13 + 17)/4
  • x = 1 cm

Note. The other root is ignored as negative.

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