已知,|b-2|+(a+b-1)^2 = 0 , 且有：|b-2| ≥ 0 ,(a+b-1)^2 ≥ 0 , 可得：b-2 = 0 ,a+b-1 = 0 , 解得：b = 2 ,a = -1 , 所以,a^50÷b^8 = 1/256 .
