题目在讲提取公因式一课时,张老师出了这样一道题目:把多项式3(x−y)3−(y−x)23\left(x-y\right)^{3}-\left(y-x\right)^{2}3(x−y)3−(y−x)2分解因式⋅\cdot⋅并请甲、乙两名同学在黑板上演算.甲演算的过程:3(x−y)3−(y−x)2=3(x−y)3+(x−y)2=(x−y)2[3(x−y)+1]=(x−y)2(3x−3y+1)3\left(x-y\right)^{3}-\left(y-x\right)^{2}=3\left(x-y\right)^{3}+\left(x-y\right)^{2}=\left(x-y\right)^{2}\left[3\left(x-y\right)+1\right]=\left(x-y\right)^{2}(3x-3y+1)3(x−y)3−(y−x)2=3(x−y)3+(x−y)2=(x−y)2[3(x−y)+1]=(x−y)2(3x−3y+1).乙演算的过程:3(x−y)3−(y−x)2=3(x−y)3−(x−y)2=(x−y)2(3x−3y)3\left(x-y\right)^{3}-\left(y-x\right)^{2}=3\left(x-y\right)^{3}-\left(x-y\right)^{2}=\left(x-y\right)^{2}(3x-3y)3(x−y)3−(y−x)2=3(x−y)3−(x−y)2=(x−y)2(3x−3y).他们的计算正确吗?若错误,请你写出正确答案.知识点：因式分解章节：数学竞赛 / 数与式
