Respostas

2014-05-14T16:42:12-03:00
a) (3x+5)² + (x+3) (x-3) = 
(9x² + 15x + 15x + 25) + x² + 3x + 3x - 9 = 
9x² + 30x + 25 + x² + 6x - 9 =
10x² + 36x + 16 = 0  (÷2)
5x² + 18x + 8 = 0

1 5 1