b)
<=>5-3x-6x-7=0
<=>-2-9x=
<=>9x=-2<=>x=-2/9
c),d chuyển vế làm tương tự
a/ 3x + 1 = 7x - 11
=> 3x - 7x = -11 - 1
=> -4x = -12
=> 4x = 12
=> x = 12 : 4
=> x = 3
thử sức xem sao https://olm.vn/hoi-dap/detail/211451950700.html?pos=476647086293
a)
<=>3x+1-7x+11=0
<=>12-4x=0
<=>4x=12
<=>x=12:4
,<=>x=3
b)
<=>5-3x-6x-7=0
<=>-2-9x=0
<=>9x=-2
<=>x=-2/9