Respostas

2014-07-17T09:27:45-03:00
(2x-5)² = 10(2x²-5)+39 <=>
<=> 4x² - 10x + 25 = 20x² - 50 + 39 <=>
<=> 4x² - 20x² - 10x = - 50 +39 - 25 <=>
<=> - 16x² - 10x = - 36<=>
<=> - 16x² - 10x + 36 = 0 

a = -16
b = - 10 
c = 36 

x =  \frac{-b+ \sqrt{b^{2} -4ac} }{2a} =  \frac{-(-10)+ \sqrt{(-10)^2-4(-16*36)} }{2(-16)}  \\< => x =  \frac{10+ \sqrt{2404} }{-32}  \\ ou \\ x =  \frac{10- \sqrt{2404} }{-32}