Respostas

2014-03-19T22:36:22-03:00
A) 7x-(-2x+x)+(-3x+5x)
   7x-3x+8x
   4x+8x=12x

b) 5y²-(-4y²+7y²)+(-y²+9y²-11y²)
  25y-(16y+49y)+(-2y+81y-111y)
  25y-65y+(-32y)
  -40y+(-32y) = (-1)
  40y+32y= 72y

  

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