( 7 ) 
( 121 ) 
= A + - B, 
2 
= A + B, (8) 
= A-iß, (9) 
=-■ A, (10) 
= 4A, (11) 
= 4A + B,. ... (12) 
= 2 A, (13) 
= 2 A + B,. . . . (14i 
= 6A — B, . . . . (15) 
= 6 A, (16) 
= 6A + B, . . . . (17) 
= 6 A + 2B, . . . (18) 
