(y-2)(y^2-6y-9)-y(y^2-2y-15),其中y=1/2.先化简再求值.

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(y-2)(y^2-6y-9)-y(y^2-2y-15),其中y=1/2.先化简再求值.
(y-2)(y^2-6y-9)-y(y^2-2y-15),其中y=1/2.先化简再求值.

(y-2)(y^2-6y-9)-y(y^2-2y-15),其中y=1/2.先化简再求值.
原式=y(y²-6y-9)-2(y²-6y-9)-y(y²-2y-15)
=y³-6y²-9y-2y²+12y+18-y³+2y²+15y
=-6y²+18y+18
=-6×1/4+18×1/2+18
=-3/2+9+18
=51/2

y (3y^2+8y-3)-6y(3y+2y-1)+9y 通分 y+3/y*y-6y+9,1/2y+6,y-1/y*y-9 (y-2)(y^2-6y-9)-y(y^2-2y-15),其中y=1/2.先化简再求值. (y^2)^4y-(-2y)^3y^6= y Y. Y Y y Y -y y Y Y (^.^)y-~ y y 【2(x-y)(x-y)(x-y)-8(x-y)(x-y)(x+y)+6y(x-y)(x-y)]/2(x-y)(x-y)