
 
6
2  2! = 1*2 = 2 ;  
 3!*2!*10=6*2*10=120 . 
   240 .  
 
4)  5  (240+240+240 =720) .  
: 720 . 
 
  
14.  
  ) {1,2,3}×{a,b}, 
   ) {x,y}×{x,y,z}, 
  ) ×{a,b}.  
: 
) 
1
={1,2,3}; 
2
={a,b}, 
1
2
= {1,2,3}×{a,b}= {(1,), (1,b), (2,a), (2,b), (3,a), (3,b)} 
) 
1
={x,y}, 
2
={x,y,z}, 
1
2
={x,y}×{x,y,z}= {(x,x), (x,y), (x,z),  (y,x), (y,y), (y,z)} 
) 
1
=,  
2
={a,b} 
1
2
=.×{a,b}=   
 
15.    R = {(x,y)| x+y=x
2
–y
2
},  {1,2,-
1,0,7,8,9}.  
: 
x  y 
x+y=x
2
–y
2
 
2  1   
-1  1   
1  -1   
0  -1   
1  0   
0  0   
8  7   
9  8   
: (2,1); (-1,1); (1,-1); (0,-1); (1,0); (0,0); (8,7); (9,8). 
 
16.  {(1,2),(2,3),(1,3)}. 
: 
   R={(1,2),(2,3),(1,3)} . ,  
  .   
 () 
: 
R
={(1,2),(2,3),(1,3),(1,1),(2,2),(3,3)} 
: R={(1,2),(2,3),(1,3),(1,1),(2,2),(3,3)} 
 
17.   {(1,2),(2,3),(1,3)}. 
: 
   R={(1,2),(2,3),(1,3)} . ,  
  .   
,   : 
R
s
={(1,2),(2,3),(1,3),(2,1),(3,2),(3,1)} 
: R
s
={(1,2),(2,3),(1,3),(2,1),(3,2),(3,1)} 
 
18.  {(a,b),(d,c),(c,b),(b,c)}.