Chọn câu sai. Với \(a;b;m \in Z;b;m \ne 0\) thì

$\left\{ {1; - 1} \right\}$         

\(\left\{ 2 \right\}\)  

\(\left\{ {1;2} \right\}\)

\(\left\{ {1;2;3} \right\}\)

\(a = 3,b =  - 259\)                

\(a =  - 3,b =  - 259\)  

\(a = 3,b = 259\)

\(a =  - 3,b = 259\)

$180$ 

\(500\)  

\(750\) 

\(450\)

\(\dfrac{{16}}{{56}};\dfrac{{ - 35}}{{56}}\)        

\(\dfrac{{16}}{{56}};\dfrac{{35}}{{56}}\)  

\(\dfrac{{16}}{{56}};\dfrac{{35}}{{ - 56}}\)      

\(\dfrac{{ - 16}}{{56}};\dfrac{{ - 35}}{{56}}\)

\({3^3}{.7^2}\)                     

\({3^3}{.7^3}.11.19\)             

\({3^2}{.7^2}.11.19\)

\({3^3}{.7^2}.11.19\)

\(\dfrac{4}{9}\) 

\(31\)  

\( - 1\) 

\(4\)