Respostas

2013-09-26T22:55:13-03:00
(a + b)² = a² + 2ab + b²
(3x + 9) = (3x)
² +2(3x)9 + 9²
= 9x
² + 6x(9) + 81 = 9x² + 54x + 81
2013-09-26T23:46:33-03:00
3X+9=   3X=-9  X= \frac{-9}{3} X=3 X= \sqrt{3} =1,732050