Respostas

2013-06-19T15:51:45-03:00

x²= 2x

ou seja:

2x+8x iagual a : 10x

10 dividido por 180 

-18

  • Usuário do Brainly
2013-06-19T15:53:44-03:00

Observe que:

 

\text{x}=\dfrac{-\text{b}\pm\sqrt{\text{b}^2-4\cdot\text{a}\cdot\text{c}}}{\dfrac{2\cdot\text{a}}

 

Onde,  \Delta=\text{b}^2-4\cdot\text{a}\cdot\text{c}

 

Segundo o enunciado, \text{a}=1, \text{b}=8 e \text{c}=-180

 

Desta maneira, \Delta=8^2-4\cdot1\cdot(-180)=64+720=784

 

Logo:

 

\text{x}=\dfrac{-8\pm\sqrt{784}}{2\cdot1}=\dfrac{-8\pm28}{2}

 

As raízes são:

 

\text{x}=\dfrac{-8+28}{2}=\dfrac{20}{2}=10

 

\text{x}=\dfrac{-8-28}{2}=\dfrac{-36}{2}=-18

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