1. (2011.泉州)3a2·a3的值为 ( )
A.3a2 B.3a5 C.a6 D.a8
2.(2011.龙岩)计算(x-1)(2x+3)的结果是 ( )
A.2x2+x-3 B.2x2-x-3 C.2x2-x-3 D.x2-2x-3
3.计算2x2·(-3x3)+x5的结果是 ( )
A.-5x5 B.7x5 C.-x6 D.3x6
4.(2011.梧州)分解因式x2y-4y的正确结果是 ( )
A.y(x+2)(x-2) B.y(x+4)(x-4)
C.y(x2-4) D.y(x-2)2