Đáp án:
` 10 - 3(x-1) = -5`
` 3(x-1) = 15`
` x -1 = 5`
` x = 6
--------
` -4 < |x+3| < 2`
Ta có
`|x+3| \ge 0`
` => 0 \le |x+3| \le 2`
Vì ` |x+3| \le 2`
` => -2 \le x +3 \le 2`
` => -5 \le x \le -1`
-------------
` -10 - |5-x| = -12`
` => |5-x| = -10 +12`
` => |5-x| = 2`
TH1
` 5-x = 2`
` => x = 3`
TH2
` 5-x = -2`
` => x =7`
--------------
` -2x -40 = (5-x) - (-15 + 60)`
` -2x -40 = 5 - x + 15 - 60`
` -2x - 40 = -40 - x`
` -2x = -x`
` -2x + x = 0`
` -x = 0`
` x= 0`
