Resposta :

2^-2*2=0  4-4=0                                                         
[tex]x^2-x-2=0\\ \Delta=(-1)^2-4\cdot1\cdot(-2)\\ =1+8=9\\\\ x=\dfrac{1\pm\sqrt{9}}{2}\\\\ x_1=\dfrac{1+\sqrt{9}}{2}=2\\\\ x_2=\dfrac{1-\sqrt{9}}{2}=-1[/tex]

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