A=x^2-xy,B=xy+y^2,则A+B=___,A-B=___,3A-2B=___.

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A=x^2-xy,B=xy+y^2,则A+B=___,A-B=___,3A-2B=___.A=x^2-xy,B=xy+y^2,则A+B=___,A-B=___,3A-2B=___.A=x^2-xy,B

A=x^2-xy,B=xy+y^2,则A+B=___,A-B=___,3A-2B=___.
A=x^2-xy,B=xy+y^2,则A+B=___,A-B=___,3A-2B=___.

A=x^2-xy,B=xy+y^2,则A+B=___,A-B=___,3A-2B=___.
A+B=x²+y²
A-B=x²-2xy-y²
3A-2B=3x²-5xy-2y

A+B=x^2+y^2
A-B=x^2-y^2-3xy
3A-2B=3x^2-2y^2-5xy

A+B=x^2-xy+xy+y^2=x^2+y^2
A-B=x^2-xy-(xy+y^2)=x^2-2xy-y^2
3A-2B
=3(x^2-xy)-2(xy+y^2)
=3x^2-3xy-2xy-2y^2
=3x^2-5xy-2y^2
=(x-2y)(3x+y)