390 - (x-7 ) - 169 : 13 = 0
390 - (x-7 ) - 13 = 0
390 - (x-7) = 13 +0
390 -(x-7 ) = 13
x-7 = 390 -13
x-7 = 377
x= 377 +7
x= 384
390-(x-7)-169:13=0
390-(x-7)-13=0
390-(x-7)=0+13
390-(x-7)=13
x-7=390-13
x-7=377
x=377+7
x=384
vậy x=384
390-(x-7)-13=0
390-(x-7)=0+13
390-(x-7)=13
x-7=390-13
x-7=377
x=377+7
x=384