Respostas

2013-11-02T21:58:55-02:00
 x^{2} +x=12
 x^{2} +x-12=
 1^{2}-4.1.(-12)
1+48
49
x= \frac{-1+- \sqrt{49} }{2.1}
x= \frac{-1+-7}{2}
x'= \frac{-1+7}{2}
x'= \frac{6}{2}
x'=3
x''= \frac{-1-7}{2}
x''=-4(nao convem)
 3^{2}+3=12
9+3=12
12=12
R=3

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