数学题若x是纯虚数，y是实数，且2x
若x是纯虚数，y是实数，且2x-1+i=y-(3-y)i,则x+y=( ) A.1+5|2i B.-1+5|2i .1-5|2i D.-1-5|2i
设x=ia,y=b 2x-1+i=y-(3-y)i 2ai-1+i=b-(3-b)i -1-(-2a-1)i=b-(3-b)i b=-1,3-b=-2a-1,a=-5/2 x+y=-1-5/2i 选D