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x+y=0.5 x+3y=1.2 求3x2 +12xy +9y2
人气:108 ℃ 时间:2020-10-01 21:20:57
解答
∵x+y=0.5 x+3y=1.2
∴3x2 +12xy +9y2
=3(x²+4xy+3y²)
=3(x+y)(x+3y)
=3×½×1.2
=1.8
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