Răspuns :
51 -(2660 :76 + x) : 23=28
( 2660 : 76 + x) : 23=51-28
( 2660:76 + x) :23= 23
35+ x=23 x 23
35+ x=529
x=529-35
x=494
51- ( 2660 : 76 +x ) : 23 = 28
51- ( 35 + x ) : 23 = 28
51-( 35+x ) = 28×23
51- ( 35+x ) = 644
35+x = 644 - 51
35+x = 593
x = 593 -35
x = 558
51- ( 35 + x ) : 23 = 28
51-( 35+x ) = 28×23
51- ( 35+x ) = 644
35+x = 644 - 51
35+x = 593
x = 593 -35
x = 558