Respostas

2014-03-30T13:46:08-03:00
(2x+3)² - 9 = 12x
4x²+9 - 9 = 12x
4x² - 12 x = 0
evidenciando o x
x(4x -12) = 0
x'=0
4x -12 = 0
4x = 12
x" = 3
1 1 1
2014-03-30T13:52:47-03:00
(2x+3)²-9=12x  
(2x+3) . (2x+3) - 9 = 12x
4x² + 6x + 6x +9 - 9 = 12x
4x² +12x -12x=0
4x²=0
x²= 0/4
x=0
1 1 1