|2a-b|为非负数,即大于等于0(b-1)²同上|2a-b|与(b-1)²互为相反数则|2a-b|与(b-1)²都为0所以2a-b=0,b-1=0b=1,a=1/2(a+b)³=(1+1/2)³=27/8
|2a-b|与(b-1)²互为相反数即|2a-b|+(b-1)²=0必有 2A-B=0,B-1=0 ==>B=1,A=1/2所以(A+B)^3=(1/2+1)^3=27/8
因为都非负,所以2a-b=0,b=1,a=1/2.所以(a+b)^3=27/8