根号2x-y+丨2y+4丨=0,则x²-2y的值为根号2x-y+丨2y+4丨=0,则x²-2y的结果为多少?2x-y在根号里,丨2y+4丨是绝对值

根号2x-y+丨2y+4丨=0,则x²-2y的值为
根号2x-y+丨2y+4丨=0,则x²-2y的结果为多少?
2x-y在根号里,丨2y+4丨是绝对值

即
√2x-y+/2y+4/=0
∵√2x-y≥0
/2y+4/≥0
∴2x-y=0
2y+4=0
∴y=-2
∴x=-1
∴x²-2y
=1+4
=5