Respostas

2014-04-19T15:53:18-03:00
-7
42+7= 49
(-7}²= (-7).(-7)= 49
1 1 1
2014-04-19T15:57:11-03:00
-x² - 7 = 42
-x² = 42 + 7
-x² = 49 
 x = (-7) . (-7) = 49
1 1 1