作业帮A=4x²-2xy+4y²,B=3x²-6xy+3y²,且|x|=3.y²=16,|x+y|=1,求4A+[(2A-B)-3(A+B)]的值
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![A=4x²-2xy+4y²,B=3x²-6xy+3y²,且|x|=3.y²=16,|x+y|=1,求4A+[(2A-B)-3(A+B)]的值](/uploads/image/z/1616359-31-9.jpg?t=A%3D4x%26sup2%3B-2xy%2B4y%26sup2%3B%2CB%3D3x%26sup2%3B-6xy%2B3y%26sup2%3B%2C%E4%B8%94%7Cx%7C%3D3.y%26sup2%3B%3D16%2C%7Cx%2By%7C%3D1%2C%E6%B1%824A%2B%5B%282A-B%29-3%28A%2BB%29%5D%E7%9A%84%E5%80%BC)
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A=4x²-2xy+4y²,B=3x²-6xy+3y²,且|x|=3.y²=16,|x+y|=1,求4A+[(2A-B)-3(A+B)]的值
A=4x²-2xy+4y²,B=3x²-6xy+3y²,且|x|=3.y²=16,|x+y|=1,求4A+[(2A-B)-3(A+B)]的值
A=4x²-2xy+4y²,B=3x²-6xy+3y²,且|x|=3.y²=16,|x+y|=1,求4A+[(2A-B)-3(A+B)]的值
A=4x²-2xy+4y²,B=3x²-6xy+3y²,
4A+[(2A-B)-3(A+B)]的值
=4A+[2A-B-3A-3B]
=4A-A-4B
=3A-4B
=3(4x²-2xy+4y²)-4(3x²-6xy+3y²)
=12x²-6xy+12y²-12x²+24xy-12y²
=18xy
且|x|=3.y²=16,|x+y|=1,
x=±3 y=±4 x+y=±1
(1)x=3 y=-4
则上式=18xy=18*3*(-4)=-216
(2)x=-3 y=4
则上式=18xy=18*(-3)*4=-216