求值:y^n(y^n+9y-12)-3(3Y^n+1-4y^n),其中,y=-3,n=2
问题描述：
求值:y^n(y^n+9y-12)-3(3Y^n+1-4y^n),其中,y=-3,n=2
答
(-3)^2×[(-3)^2+9×(-3)-12]-3×[3×(-3)^2+1-4×(-3)^2]
=-246
答
y^n(y^n+9y-12)-3(3Y^n+1-4y^n)
=y^2n+9y^(n+1)-12y^n-9y^(n+1)+12y^n
=y^2n
=(-3)^(2×2)
=81