(x + 1)2 - (x + 1)(x - 1) = 0
\(\Rightarrow\) x2 + 2x + 1 - x2 + 1 = 0
\(\Rightarrow\) 2x + 2 = 0
\(\Rightarrow\) 2x = - 2
\(\Rightarrow\) x = - 1
Vậy x = - 1
\(\left(x+1\right)^2-\left(x+1\right).\left(x-1\right)=0\)
\(\Rightarrow\left(x+1\right).\left(x+1\right)-\left(x+1\right).\left(x-1\right)=0\)
\(\Rightarrow\left(x+1\right).\left[\left(x+1\right)-\left(x-1\right)\right]=0\)
\(\Rightarrow\left(x+1\right).\left[x+1-x+1\right]=0\)
\(\Rightarrow\left(x+1\right).\left[\left(x-x\right)+\left(1+1\right)\right]=0\)
\(\Rightarrow\left(x+1\right).\left[0+2\right]=0\)
\(\Rightarrow\left(x+1\right).2=0\)
\(\Rightarrow x+1=0:2\)
\(\Rightarrow x+1=0\)
\(\Rightarrow x=0-1\)
\(\Rightarrow x=-1\)