3(x - 1) - (x - 5 ) = -18
=> 3x - 3 - x + 5 = -18
=> 2x + 2 = -18
=> 2x = -20
=> x = -10
Vậy.....
3(x - 1) - (x - 5 ) = -18
3x - 3 - x + 5 = -18
2x + 2 = -18
2x = -20
x = -10
3(x-1)-(x-5) = -18
<=>3x-3-x+5=-18
<=>2x+2=-18
<=>2x=-18-2
<=>2x=-20
<=>x=-20:2
<=>x=-10