Respostas

2014-05-10T14:28:49-03:00
X² - 15x = - 3x
x² - 15x + 3x = 0
x² - 12x = 0

x em evidência

x ( x - 12) = 0
x = 0
x - 12 =0 , x = 12

S = ( 0 , 12)
2014-05-10T14:31:30-03:00
X²-15x=-3x
x²-15x+3x=0 
x²-12x =0 

Δ=b²-4ac
Δ=(-12)²-4.1.0
Δ=144 

x=-b+-√Δ / 2a
x=-(-12)+-√144 / 2.1 
x=12+-12/2

x'=12+12/2
x'= 12

x''=12-12/2
x''=0 

x'=12
x''= 0