( 42 + x ) : 3 = 5
42 + x = 5 x 3
42 + x = 15
x = 42 - 15
x = 27
( 42 + x ) : 3 = 5
42+x=5*3
42+x=15
x=42-15
x=27
(42+x):3=5
42+x=5 x 3
42+x=15
x=15-42
x=-27
(42+x):3=5
42+x =5x3
42+x =15
x =15-42
x =-27
Vậy x=-27
( 42 + x ) : 3 = 5
42 + x = 5 x 3
42 + x = 15
x = 15 - 42
x = -27