18题,
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18题,18题, 18题,=(x+y-x+y)/{(x-y)(x+y)}*(x^2+2xy+y^2)/2y=(x+y)^2/(x-y)(x+y)=(x+y)/(x-y)带入x+y=2√3x-
18题,
18题,
18题,
=(x+y-x+y)/{(x-y)(x+y)}*(x^2+2xy+y^2)/2y
=(x+y)^2/(x-y)(x+y)
=(x+y)/(x-y)
带入
x+y=2√3
x-y=2√2
所以原式就等于2√3/2√2=(√6)/2