Respostas

2014-02-03T10:12:06-02:00
X^2+2x-21=0

∆-= b^2-4ac
∆= 2^2- 4.1(-21)
∆=4+84
∆=88
x= -b ± raiz de ∆ / 2a
x= -2± raiz de 88/2
x= -2 ± 2 raiz de 22/2         cancela-se os 2
x= ± raiz de 22
x'= raiz de 22
x"= - raiz de 22
S{± raiz de 22}
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