Question

初二下册数学一道分式题若x/y=3,求x²+2xy-3y²/x²+2xy+y²的

Answer 1

原式=(x+3y)*(x-y)/(x+y)/(x+y)

=(x/y+3)*(x/y-1)/(x/y+1)/(x/y+1)

=(3+3)(3-1)/(3+1)/(3+1)

=6*2/4/4

=3/4.

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