①请写出三个与3x2y2z是同类项的单项式．②若2x2ym与12xny2是同类项，则m=，n=．③把多项式2x4-1+2x2-3x3-12x按x的降幂排列为2x4−3x3+2x2−12x−12x4−3x3+2x2−12x−1．

Question

①请写出三个与3x²y²z是同类项的单项式______．
②若2x²y^m与(1)/(2)xny2是同类项，则m=______，n=______．
③把多项式2x⁴-1+2x²-3x³-(1)/(2)x按x的降幂排列为

2x4−3x3+2x2−(1)/(2)x−1

2x4−3x3+2x2−(1)/(2)x−1

．

Answer 1

①-x²y²z，2x²y²z，6x²y²z；
②由同类项的定义可知n=2，m=2；
③把多项式按x的降幂排列为2x⁴-3x³+2x²-(1)/(2)x-1．