计算 （3X²+2Xy-1/2x）-﹙2x²-xy+x﹚ ﹙1/2xy+y²+1﹚+﹙x²-1/2xy-2y²-1﹚ -﹙x²y+3xy-4﹚+3﹙x²y-xy+2﹚ -1/4﹙2k ³-2k ²+4k﹚

计算 （3X²+2Xy-1/2x）-﹙2x²-xy+x﹚ ﹙1/2xy+y²+1﹚+﹙x²-1/2xy-2y²-1﹚ -﹙x²y+3xy-4﹚+3﹙x²y-xy+2﹚ -1/4﹙2k ³-2k ²+4k﹚
计算 （3X²+2Xy-1/2x）-﹙2x²-xy+x﹚ ﹙1/2xy+y²+1﹚+﹙x²-1/2xy-2y²-1﹚ -﹙x²y+3xy-4﹚+3﹙x²y-xy+2﹚ -1/4﹙2k ³-2k ²+4k﹚

计算 （3X²+2Xy-1/2x）-﹙2x²-xy+x﹚ ﹙1/2xy+y²+1﹚+﹙x²-1/2xy-2y²-1﹚ -﹙x²y+3xy-4﹚+3﹙x²y-xy+2﹚ -1/4﹙2k ³-2k ²+4k﹚
（3X²+2Xy-1/2x）-﹙2x²-xy+x﹚
=3x²+2xy-1/2x-2x²+xy-x
=x²+3xy-3/2x
﹙1/2xy+y²+1﹚+﹙x²-1/2xy-2y²-1﹚
=1/2xy+y²+1+x²-1/2xy-2y²-1
=x²-y²
-﹙x²y+3xy-4﹚+3﹙x²y-xy+2﹚
=-x²y-3xy+4+3x²y-3xy+6
=2x²y-6xy+10
-1/4﹙2k ³-2k ²+4k﹚
=-1/2k³+1/2k²-k

1. 原式=3x^2+2xy-x/2-2x^2+xy-x=x^2+3xy-3x/2

2. 原式=xy/2+y^2+1+x^2-xy/2-2y^2-1=-y^2+x^2

3. 原式=-x^2y-3xy+4+3x^2y-3xy+6=2x^2y-6xy+10

4. 原式=-k^3/2+k^2/2-k

照成图片发过来。1/2x中的x是在分母上还是分子上。