3(x+3) -4.(x+3) =0 корен на уравнение?

(х+3)(1-4)=0
-3(х+3)=0
х+3=0
х=-3

(х+3)³-4*(х+3) = 0
(х+3)(х+3)²-4(х+3) = 0
(х+3)*(х²+6х+9-4) = 0
х+3 = 0
х1 = х²+6х+5 = 0
D = 36-20 = 16
√D = 4
x2 = (-6+4)\2 = -1
x3 = (-6-4)\2 = -5
ответ: -3; -1; -5