Respostas

2014-06-24T19:02:04-03:00
9x+81=36
9x=36-81
9x=-45
x=-5
2014-06-24T19:15:12-03:00
(3x-9) ^{2} = 36

9x²-54x +81=36

9x²-54x+45=0  (: por 9)

x²-6x +5=0

Δ=36-20=16
√Δ=4

x'= \frac{6+4}{2} = \frac{10}{2} = 5

x"= \frac{6-4}{2} =  \frac{2}{2} = 1

S={1;5}

2 5 2