Respostas

2014-08-10T12:36:47-03:00
X + x² = 90
x² + x - 90 = 0
x = [-b +- raiz de ( b²-4ac)]/ 2a
x = (-1 +- raiz de 361)/2
x= (-1 +- 19)/2
x' = 9 ou x''= -10


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