【上岸】評論
a=-7,b=12 (A) | a+b |= | -7+12 |= | 5|= 5(B) | a-b |= | -7-12 |= |-19 |= 19(C) | a |+| b | = | -7 |+| 12 |=7+ 12 = 19(D) | a |-| b |= | -7 |-| 12 |=7 - 12 =-5D選項為最小