Respostas

2013-06-07T19:27:21-03:00

=(7+a).(5+a)

=35+7a+5a+a^{2}

=a^{2}+12a+35

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2013-06-07T19:31:46-03:00

7x5=35 , 7xa=7a:  5x7=35 , 5xa=5a;  35.7a.35.5a=35.35.5a.7a=1225.7a.5a

1225.35a 35a=-1225 : a= 1225/35 a= 245

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