先化简,再求值:(y-2)(2y²-3y+9)-y(y²-2y+15),其中Y²-4Y-4=0.
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/19 09:15:10
![先化简,再求值:(y-2)(2y²-3y+9)-y(y²-2y+15),其中Y²-4Y-4=0.](/uploads/image/z/2483051-59-1.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80%2C%E5%86%8D%E6%B1%82%E5%80%BC%EF%BC%9A%28y-2%29%282y%26%23178%3B-3y%2B9%29-y%28y%26%23178%3B-2y%2B15%29%2C%E5%85%B6%E4%B8%ADY%26%23178%3B%EF%BC%8D4Y-4%3D0.)
x){gu
:OzmlzڰYFFjʆֺƕږ0QmOvkkbkgTOslhbRJlb&`5qF+l`HJ,*MTTjc(6JiUeWd)34YJ656в!HŌ4᠉2
L]##<;P|
先化简,再求值:(y-2)(2y²-3y+9)-y(y²-2y+15),其中Y²-4Y-4=0.
先化简,再求值:(y-2)(2y²-3y+9)-y(y²-2y+15),其中Y²-4Y-4=0.
先化简,再求值:(y-2)(2y²-3y+9)-y(y²-2y+15),其中Y²-4Y-4=0.
y²-4y-4=0.
y²-4y=4
(y-2)(2y^2-3y+9)-y(y^2-2y+15)
=(y-2)(2y^2-8y+5y+9)-y(y^2-4y+2y+15)
=(y-2)[2(y^2-4y)+5y+9]-y(y^2-4y+2y+15)
=(y-2)[2*4+5y+9]-y(4+2y+15)
=(y-2)(5y+17)-y(2y+19)
=5y^2+7y-34-2y^2-19y
=5y^2-2y^2-19y+7y-34
=3y^2-12y-34
=3(y²-4y)-34
=3*4-34
=12-34
=-22