1. 口算：
(1)$6x^{2}· 3xy^{2}=$
； (2)$2x^{2}y· \frac {3}{2}xy=$
；
(3)$2ab^{2}· (-5ab^{4})=$
； (4)$4x^{2}y· (-x^{3}y^{6})=$
.
答案：1. (1) $ 18x^{3}y^{2} $ (2) $ 3x^{3}y^{2} $ (3) $ -10a^{2}b^{5} $ (4) $ -4x^{5}y^{7} $
2. 计算：
(1)$(2x)^{3}· (-5xy^{2})$； (2)$3x^{2}y· (-2x^{3}y^{2})^{2}$；
(3)$2x^{4}· x^{2}+(-3x^{3})^{2}-5x^{6}$； (4)$a^{4}· 3a^{2}+(-2a^{2})^{3}+5a^{6}$；
(5)$2a^{2}· a^{4}+(a^{3})^{2}$； (6)$(-2x^{3})^{2}· x-x^{3}· x^{4}+(-x)^{7}$；
(7)$(3a)^{2}· a^{4}+a· a^{5}-(-a^{3})^{2}$； (8)$3a^{2}· 2a^{4}-(3a^{3})^{2}+4a^{6}$；
(9)$n^{2}· n^{4}+4(n^{2})^{3}-5n^{3}· n^{2}$； (10)$a^{3}· a^{4}· a+(a^{2})^{4}+(-2a^{4})^{2}$.
答案：2. (1) $ -40x^{4}y^{2} $ (2) $ 12x^{8}y^{5} $ (3) $ 6x^{6} $ (4) 0 (5) $ 3a^{6} $ (6) $ 2x^{7} $ (7) $ 9a^{6} $ (8) $ a^{6} $ (9) $ 5n^{6}-5n^{5} $ (10) $ 6a^{8} $
解析：
(1) $(2x)^{3}· (-5xy^{2})=8x^{3}· (-5xy^{2})=-40x^{4}y^{2}$
(2) $3x^{2}y· (-2x^{3}y^{2})^{2}=3x^{2}y· 4x^{6}y^{4}=12x^{8}y^{5}$
(3) $2x^{4}· x^{2}+(-3x^{3})^{2}-5x^{6}=2x^{6}+9x^{6}-5x^{6}=6x^{6}$
(4) $a^{4}· 3a^{2}+(-2a^{2})^{3}+5a^{6}=3a^{6}-8a^{6}+5a^{6}=0$
(5) $2a^{2}· a^{4}+(a^{3})^{2}=2a^{6}+a^{6}=3a^{6}$
(6) $(-2x^{3})^{2}· x-x^{3}· x^{4}+(-x)^{7}=4x^{6}· x - x^{7} - x^{7}=4x^{7}-x^{7}-x^{7}=2x^{7}$
(7) $(3a)^{2}· a^{4}+a· a^{5}-(-a^{3})^{2}=9a^{2}· a^{4}+a^{6}-a^{6}=9a^{6}+a^{6}-a^{6}=9a^{6}$
(8) $3a^{2}· 2a^{4}-(3a^{3})^{2}+4a^{6}=6a^{6}-9a^{6}+4a^{6}=a^{6}$
(9) $n^{2}· n^{4}+4(n^{2})^{3}-5n^{3}· n^{2}=n^{6}+4n^{6}-5n^{5}=5n^{6}-5n^{5}$
(10) $a^{3}· a^{4}· a+(a^{2})^{4}+(-2a^{4})^{2}=a^{8}+a^{8}+4a^{8}=6a^{8}$
