42÷d×3=21÷7
(b÷3)×6=52-4


Răspuns :

42:dx3=3
dx3=126
d=126:3
d=42

(b:3)x6=48
b:3=48:6
b:3=8
b=3x8
b=24
42:d•3=21:7
42:d•3=3
42:d=3:3
42:d=1
d=42•1
d=42


(b:3)•6=52-4
(b:3)•6=48
b:3=48:6
b:3=8
b=8•3
b=24