A) 25 - 15 : x = 20
15 : x = 25 - 20
15 : x = 5
x = 15 : 5
x = 3
B) x - [ 42 + ( - 28 ) ] = -8
x - 14 = - 8
x = ( - 8 ) + 14
x = 6
chúc bn hok tốt @_@
A) 25 - 15 : x = 20
15 : x = 25 - 20
15 : x = 5
x = 15 : 5
x = 3
B) x - [ 42 + ( - 28 ) ] = -8
x - 14 = - 8
x = ( - 8 ) + 14
x = 6
A) 25-15:x=20
15:x=25-20
15:x=5
x=15:5
x=3
vayx=3
B) x-[42+(-28)]=-8
x- 14 =-8
x =(-8)+14
x = 6
vay x=6