(2x^2+ax-3-y)-(2y+2bx^2-3x-1)的值與字母X的取值無關(guān)
(2x^2+ax-3-y)-(2y+2bx^2-3x-1)
=2x^2+ax-3-y-2y-2bx^2+3x+1
=(2-2b)x^2+(a+3)x-2-3y
2-2b=0 a+3=0
b=1 a=-3
多項式3/1a^3-b^2-4/1(a^3-12b^2)的值
3/1a^3-b^2-4/1(a^3-12b^2)
=3/1*(-3)^3-1^2-4/1((-3)^3-12*1^2)
=3/1*(-27)-1-4/1(-27-12)
=-9-1-4/(-39)
=-19又4/3