Respostas

2014-04-16T11:12:43-03:00
〖16x〗^2-4x-5=0

16x² - 4x - 5 = 0            a= 16         b= -4           c = -5
Δ= b² - 4ac
Δ= (-4)² - 4(16)(-5)
Δ= 16 + 320
Δ= 336        se  Δ>0     então      x =  - b = - √Δ/2a

x' =  -(-4) - √ 336/ 2(16)
x' =  +4   - √336/32                              fatorando            336| 2
                                                                                       168| 2
                                                                                         84| 2
                                                                                         42| 2
                                                                                         21| 3
                                                                                           7| 7
                                                                                                                                então:     √336  =   2.2.2.2.3.7  =  2² . 2² . 3¹. 7¹  =  2.2√3.7  =  4√21
continuando
x' = + 4  - √336/32
x' = + 4 - 4√21                + 1 - 1√21                 + 1 - √21
       --------------  =     x'    -------------   =  x'=      ------------
            32                              8                                8


       +4 + 4√21               + 1   + 1√21              + 1+ √21
x" = -------------  =     x"=  ---------------  =    x"=  ------------
            32                              8                                8   

   

 





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