Question

Anh em giải hộ mình cái

Tìm x,biết 5x+5 chia hết cho 2x+3

 

Answer 1

\(\left(5x+5\right)⋮\left(2x+3\right)\)\(\Rightarrow2\left(5x+5\right)⋮\left(2x+3\right)\)

\(\Rightarrow\left(10x+10\right)⋮\left(2x+3\right)\)\(\Rightarrow5\left(2x+3\right)-5⋮\left(2x+3\right)\)

Vì \(5\left(2x+3\right)⋮\left(2x+3\right)\)\(\Rightarrow\)Để \(\left(5x+5\right)⋮\left(2x+3\right)\)thì \(-5⋮\left(2x+3\right)\)

\(\Rightarrow2x+3\inƯ\left(-5\right)=\left\{\pm1;\pm5\right\}\)

\(\Rightarrow x\in\left\{-4;-2;-1;1\right\}\)

Vậy \(x\in\left\{-4;-2;-1;1\right\}\)

Answer 2

Ta có \(5x+5⋮2x+3\Rightarrow10x+10⋮2x+3\)\(\Rightarrow5-\frac{5}{2x+3}\inℤ\Rightarrow2x+3\inƯ\left(5\right)\)

chắc từ đây giải đc rồi