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(1)m^2-4m+4(2)x^2+4x+4y^2(3)4x^2+2xy+1/4y^2(4)x^2-xy+y^2(5)x^2-6x-9
(6)-x^2+x-0.25
人气:299 ℃ 时间:2020-01-30 08:17:17
解答
x²+y²
=(x+y)²-2xy
=(-5)²-2×3
=25-6
=19
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