4x -(-7) = 27
=> 4x = 27 + (-7)
=> 4x = 20
=> x = 20:4
=> x =5
/x-1/ =0
=> x-1=0
=> x =0+1
=> x = 1
a . suy ra : x - 1 = 0 nên x = 1 b 4x = 27 + ( - 7 ) 4x = 20 x = 20 : 4 x = 5
x= 1
4x-(-7) = 27
=> 4x= 27+(-7) = 20
=> x= 20:4 = 5
vậy x= 5
tick nhé bn