Question

(45:b):3=3 (c:7):8=56

Answer 1

(45:b):3=3
45:b=3x3
45:b=9
B=45:9
B=5

(c:7):8=56
C:7=56x8
C:7=448
C=448x7
C=3136

Answer 2

( 45 : b ) : 3 = 3 
45 : b = 3 × 3 
45 : b = 9 
b = 45 : 9 
b = 5 

Verific:     ( 45 : 5 ) : 3 = 9 : 3 = 3 

( c : 7 ) : 8 = 56 
c : 7 = 56 × 8 
c : 7 = 448 
c = 448 × 7 
c = 3 136 

( c × 7 ) × 8 = 56 
c × 7 = 56 : 8 
c × 7 = 7 
c = 7 : 7 
c = 1