【知能点分类训练】
知能点1 单项式与多项式相乘法则
1.计算:2xy(x2y -3xy2)=________,(-a2)(2a2-3a+1)=________.
2.化简(3x2)3-7x3[x3-x(4x2+1)]等于( ).
A.31x6-7x9+ 7x4 B.9x6+7x3 C.27x5-7x9+28x6-7x3 D.48x6+7x4
3.a3-2a(3a-4b+5c)的计算结果是( ).
A.a3+6a+8ab-10abc B.a3-6a2+8ab-10ac
C.a2-6a3+8ab+10ac D.a3-6a2-8ab+10abc
4.下列各式计算正确的是( ).
A.(a-3b)(-6a)=-6a2-18ab B.(-x2y)(-9xy+1)=3x3y2+1
C.(a2b)2·(-4ab2)=4a3b4 D.(ab2- 2ab)(-ab)=-a2b3+a2b2