化简求值,3x^2+2xy一4y^2一(3xy一4y^2+3x^2),其中x=3,y=2

问题描述:

化简求值,3x^2+2xy一4y^2一(3xy一4y^2+3x^2),其中x=3,y=2

3x^2+2xy-4y^2-(3xy-4y^2+3x^2)
=3x^2+2xy-4y^2-3xy+4y^2-3x^2
=-xy
=-3*2
=-6
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