10. 计算下列各式:
(1)$x\cdot(-x)^{2}(-x)^{3}$;
(2)$(-2x^{2})^{3}+x^{2}\cdot x^{4}-(-3x^{3})^{2}$;
(3)$2x^{4}+x^{2}+(x^{3})^{2}-5x^{6}$;
(4)$a\cdot a^{2}\cdot a^{3}+(-2a^{3})^{2}-(-a)^{6}$.
答案:
(1)$-x^{6}$;
(2)$-16x^{6}$;
(3)$-4x^{6}+2x^{4}+x^{2}$;
(4)$4a^{6}$
11. 已知$n$为正整数,且$a^{2n}= \frac{1}{2}$,求$(4a^{3n})^{2}-32(a^{3})^{4n}$的值.
答案:解:$\because n$为正整数,且$a^{2n}=\frac{1}{2}$,$\therefore (4a^{3n})^{2}-32(a^{3})^{4n}=16a^{6n}-32a^{12n}=16(a^{2n})^{3}-32(a^{2n})^{6}=16×\left( \frac{1}{2}\right)^{3}-32×\left( \frac{1}{2}\right)^{6}=16×\frac{1}{8}-32×\frac{1}{64}=2-\frac{1}{2}=\frac{3}{2}$.
12. 阅读下列解题过程:
比较$2^{100}与3^{75}$的大小.
解:因为$2^{100}= (2^{4})^{25}$,$3^{75}= (3^{3})^{25}$,又因为$2^{4}= 16$,$3^{3}= 27$,且$16 < 27$,所以$2^{100}<3^{75}$.
根据上述解答,请比较$3^{100}与5^{60}$的大小.
答案:解:$\because 3^{100}=(3^{5})^{20}=243^{20}$,$5^{60}=(5^{3})^{20}=125^{20}$,又$243>125$,$\therefore 3^{100}>5^{60}$.