Respostas

2013-05-31T19:44:02-03:00

vou te dar um exemplo:

x²-144=0

x²=144

x=+- raiz de 144

x=+-12

 /          \

x´=12    x``= -12

 

espero ter ajudado

  • Usuário do Brainly
2013-05-31T20:01:07-03:00

a) \text{x}^2-4\text{x}=0

 

\text{x}\cdot(\text{x}-4)=0

 

\text{x}'=0

 

\text{x}''=4

 

 

b) 8\text{x}-158

 

8\text{x}=158

 

\text{x}=\dfrac{158}{8}=\dfrac{79}{4}

 

 

c) \text{x}^2-7\text{x}+12=0

 

\text{x}=\dfrac{-(-7)\pm\sqrt{(-7)^2-4\cdot1\cdot12}}{2\cdot1}=\dfrac{7\pm1}{2}

 

Logo, as raízes são:

 

\text{x}'=\dfrac{7+1}{2}=4

 

\text{x}"=\dfrac{7-1}{2}=3