Question

Tìm x biết 

x³+3x²+3x+1-3x²-3x=0

Answer 1

x²+3x²+3x+1-3x²-3x = 0

  => x³+1 = 0

  => x³     = 0-1

  => x³     = -1

  => x       = -1

Answer 2

\(x^3+3x^2+3x+1-3x^2-3x=0\)0

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

\(\Leftrightarrow x^3+1=0\)

\(\Leftrightarrow x^3=1\)

\(\Leftrightarrow x^3=1^3\)

\(\Rightarrow x=1\)