Question

Giúp mình nhé.

Tìm x biết:

a) x³ - 6x² + 12x - 8 = 0

b)x³ + 9x² +27x + 27 = 0

c) 8x³ - 12x² + 6x = 1

d) x³ - 3x² + 3x = 28 

Answer 1

a.\(x^3-6x^2+12x-8=0\Rightarrow\)\(\left(x-2\right)^3=0\Rightarrow x=2\)

b.\(x^3+9x^2+27x+27=0\Rightarrow\left(x+3\right)^3=0\)\(\Rightarrow x=-3\)

Answer 2

c. \(8x^3-12x^2+6x-1=0\)

\(\Rightarrow\left(2x-1\right)^3=0\)

\(\Rightarrow x=\frac{1}{2}\)