x方-y方
=x²-xy+xy-y²
=(x²-xy)+(xy-y²)
=60+40
=100
2x方-5xy+3y方
=2x²-2xy-3xy+3y²
=2(x²-xy)-3(xy-y²)
=120-120
=0
已知x方-xy=60,xy-y方=40,求代数式x方-y方和2x方-5xy+3y方的值.ps:
已知x方-xy=60,xy-y方=40,求代数式x方-y方和2x方-5xy+3y方的值.ps:
数学人气:407 ℃时间:2019-09-29 06:09:56
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