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已知x-y+z=0,求(x²-y²-z²)-4y²z²等于多少?
人气:456 ℃ 时间:2020-05-13 21:25:34
解答
(x²-y²-z²)²-4y²z²=(x²-y²-z²)²-(2yz)²=(x²-y²-z²-2yz)(x²-y²-z²+2yz)=[x²-(y+z)²](x...
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