已知x+y=2 求(x²-y²)²-8(x²+y²)的值
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/18 01:22:58
![已知x+y=2 求(x²-y²)²-8(x²+y²)的值](/uploads/image/z/3985551-63-1.jpg?t=%E5%B7%B2%E7%9F%A5x%2By%3D2+%E6%B1%82%28x%26%23178%3B-y%26%23178%3B%29%26%23178%3B-8%28x%26%23178%3B%2By%26%23178%3B%29%E7%9A%84%E5%80%BC)
x){}K++mmlҨPS64֭КPLB&|Vӆ=6IE_`gC VhfF.©̄8#mJJ 1<.P;P6Dr
l@ y
已知x+y=2 求(x²-y²)²-8(x²+y²)的值
已知x+y=2 求(x²-y²)²-8(x²+y²)的值
已知x+y=2 求(x²-y²)²-8(x²+y²)的值
(x²-y²)²-8(x²+y²)
=(x+y)^2(x-y)^2-8(x²+y²)
=4(x-y)^2-8(x²+y²)
=4x^2+4y^2-8xy-8x^2-8y^2
=-4(x^2+y^2+2xy)
=-4(x+y)^2
=-16