Question

Me ajudemmmmm a resolver
-3x²+15x+15=0

Answer 1

-9x+15x+15=0
-6x=0-15
-6x=15
X=15/-6
X= -2,5

Answer 2

-3x²+15x+15=0

a = -3 ; b= 15 ; c = 15 

▲ = b² - 4ac = (15)² - 4(-3)(15)
▲ = 225 +180 = 405 

x = (-b ± √▲)/2a

x1 = -1/6*(-15 - 9√5) = 3/6(5 + 3√5) = 1/2(5 + 3√5)
x1 = -1/6*(-15 + 9√5) = 3/6(5 - 3√5) = 1/2(5 - 3√5)

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13/10/2016
Sepauto 
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