Question

( 2x - 1 ) chia hết ( x + 2 )

Answer 1

\(\left(2x-1\right)⋮\left(x+2\right)\\ \Rightarrow\left(2x+4-5\right)⋮\left(x+2\right)\\ \Rightarrow\left[2\left(x+2\right)-5\right]⋮\left(x+2\right)\)

\(Mà2\left(x+2\right)⋮\left(x+2\right)\Rightarrow-5⋮\left(x+2\right)\Rightarrow x+2\inƯ\left(-5\right)=\left\{\pm1;\pm5\right\}\Rightarrow x\in\left\{-7;-3;-1;3\right\}\)

Answer 2