第156页 - 启东中学作业本七年级数学苏科版宿迁专版

-4

9

$1.25×10^{-4}$

3

4

$\frac{27}{8}$

1

0，2，4

$ \begin{aligned}解：原式&=1-4+2 \\ &=-1. \\ \end{aligned}$

$ \begin{aligned}解：原式&=a⁶+4a⁶ \\ &=5a⁶. \\ \end{aligned}$

$ \begin{aligned}解：原式&=(x-y)^6÷(y-x)^{-3}·(y-x) \\ &= (y-x)^{6+3+1} \\ &=(y-x)^{10}. \\ \end{aligned}$

$ \begin{aligned}解：原式&=(-2)⁶ ·a⁶-(-3)² ·(a³)²+(-1)³·(2a)⁶ \\ &=64a⁶-9a⁶-64a⁶ \\ &=-9a⁶. \\ \end{aligned}$

$ \begin{aligned}解：原式&=4-4+1 \\ &=1. \\ \end{aligned}$

$ \begin{aligned} 解：原式&=7^{2m+2}×7^2÷(-7)^{2m+5} \\ &=7^{2m+4}÷(-7)^{2m+5} \\ &= -7^{-1} \\ &=-\frac{1}{7}. \\ \end{aligned}$

$ \begin{aligned}解：原式&=-32×10^{15}÷10^3 \\ &=-32×10^{12} \\ &=-3.2×10^{13}. \\ \end{aligned}$

$ \begin{aligned}解：原式&= (-2)^{375}×2^4× (\frac{1}{2})^{380} \\ &=-2^{379}× (\frac{1}{2})^{380} \\ &=-(2×\frac{1}{2})^{379}×\frac{1}{2} \\ &=-\frac{1}{2}. \\ \end{aligned}$