Respostas

2014-02-17T17:28:26-03:00
A = 4 - b
b = a - 2

a = 4 - (a - 2)
a = 4 - a + 2
2a = 6
a = 6/2 = 3


3 = 4 - b
b = 4 - 3 = 1


3² - 1² = 9 - 1 = 8
9 4 9