Question

已知实数x、y满足|2x-y+1|+3根号3x-2y+4=0,求代数式[(x-y)/(x-2y)]/(x的平方-2y)/

Answer 1

绝对值和算术平方根大于等于0,相加等于0,若有一个大于0,则另一个小于0,不成立.
所以两个都等于0
所以2x-y+1=0,3x-2y+4=0
x=2,y=5
原式=(x-y)/(x-2y)(x²-2y)×(x-2y)²/(x+y)(x-y)-1
=(x-2y)/(x²-2y)(x+y)-1
=-8/(-42)-1
=-17/21