Question

(x - 1)(x + 1) - x (x + 3) = 0 

giải bài tìm x này hộ em với ạ :,)

Answer 1

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

\(\Rightarrow x^2-1-x^2-3x=0\Rightarrow-1=3x\Rightarrow x=-\dfrac{1}{3}\)

Answer 2

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

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

\(\Rightarrow3x=-1\Rightarrow x=-\dfrac{1}{3}\)

Answer 3

x²-1²  - x²- 3x=0 <=> -3x= 1 <=> x= -1/3