a) (-x + 31 ) - 39 = -69 => -x + 31 = -69 + 39 => -x = -30 + 31 => -x = -61 => x = 61
b) -121 - ( 35 - x ) = 50 => 35 - x = -121 - 50 => x = 35 - ( -171 ) => x = 206
c) 17 + x - ( 352 - 400 ) = -32 => 17 + x + 48 = -32 => x = -32 - 48 - 17 => x = -97
d) 2130 - ( x + 130 ) + 72 = -64 => 2130 - ( x + 130 ) = -64 - 72 => x + 130 = 2130 - ( -136 ) => x = 2266 - 130 => x = 2136
e) | x | - 5 = -1 => | x | = -1 + 5 => | x | = 4 => x = 4
f) | x + 2 | - 13 = -1 => | x + 2 | = -1 + 13 => x + 2 = 12 => x = 12 - 2 => x = 10
=> x + 2 = -12 => x = -12 - 2 => x = -14
g) 135 - | 9 - x | = 35 => | 9 - x | = 135 - 35 => 9 - x = 100 => x = 9 - 100 => x = -91
=> 9 - x = -100 => x = 9 - (-100) => x = 109
h) || x - 5 | - 3| = 9 => | x - 5 | - 3 = 9 => | x - 5 | = 9 + 3 => x - 5 = 12 => x = 12 + 5 => x = 17
=> x - 5 = -12 => x = -12 + 5 => x = -7
=> | x - 5 | - 3 = -9 => | x - 5 | = -9 + 3 => | x - 5 | = -6 ( loại )