Question

(𝑥 − 1)(𝑥 + 2) − 𝑥 − 2 = 0 tìm x

 

Answer 1

\(\left(x-1\right)\left(x+2\right)-x-2=0\\ \Rightarrow\left(x-1\right)\left(x+2\right)-\left(x+2\right)=0\\ \Rightarrow\left(x+2\right)\left(x-1-1\right)=0\\ \Rightarrow\left(x+2\right)\left(x-2\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=-2\\x=2\end{matrix}\right.\)

Answer 2

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

\(\Leftrightarrow x\in\left\{2;-2\right\}\)

Answer 3

( x - 1 ) ( x + 2 ) - ( x + 2 ) = 0

( x + 2 ) ( x - 1 - 1 ) = 0

( x - 2 ) ( x + 2 ) = 0

TH1 : x - 2 = 0

=> x = 2

TH2: x + 2 = 0

=> x = -2

Vậy x = 2 hoặc x = -2

Answer 4

\(\left(x-1\right)\left(x+2\right)-x-2=0\\ x^2+2x-x-2-x-2=0\\ x^2-4=0\\ x^2=4\\ x=2\)

Answer 5

thankssss các bạn rất nhiều!!!!!!!!!!!!!