Respostas

2014-02-11T17:55:59-02:00
 a) a+1+a-7=
2a-6

b) -9+5m+7x-2x=
 5x+5m-9

c) xy²+xy²+x²y= 
2xy²+x²y

d) 3x+5x+0,2x-x+2x=
 9,2x
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