(1)对
(2)对
(3)对
(4)对
2.(1)对
(2)(x方-y)·(xy方)平方=x^4y^4- x^2y^5
(3)对
(4)对
3. 对
(2)对
4.化简求值:x方(1/4x-1)-1/4x(x方-2x-4)
=1/4x³-x²-1/4x³+1/2x²+x
=-1/2x²+x
=-1/2x1/2²+1/2
=-1/8+1/2
=3/8
3.(2)x(x^2+3)+x^2(x-3)-3x(x^2-x-1)
=x^3...........+3x
+x^3-3x^2
-3x^3+3x^2+3x
=-x^3.............+6x.
4.x^2(x/4-1)-x/4*(x^2-2x-4)
=x^3/4-x^2
-x^3/4+x^2/2+x
=..........-x^2/2+x,
x=1/2时原式=-1/8+1/2=3/8.
第4题不对,其他都对。