Đáp án:
-400
Giải thích các bước giải:
Bài 1:
1. \(\begin{array}{l}
- 69.|3 - 7| - 31.|16 - 20|\\
= - 69.4 - 31.4\\
= - 4(69 + 31) = - 4.100 = - 400
\end{array}\)
2. \(\begin{array}{l}
( - 4).2:{\rm{[}}17 - (24 - 27).2)\\
= - 8:{\rm{[}}17 - ( - 3).2]\\
= - 8:(17 + 6) = - 8:23 = \frac{{ - 8}}{{23}}
\end{array}\)
3. \(\begin{array}{l}
- ( - 347) + ( - 40) + | - 2021| - | + 307|\\
= 347 - 40 + 2021 - 307\\
= (347 - 40 - 307) + 2021 = 2021
\end{array}\)
Bài 2:
1. \(\begin{array}{l}
10 - 3(1 - x) = - 5\\
\Leftrightarrow 3(1 - x) = 10 + 5 = 15\\
\Leftrightarrow 1 - x = 15:3 = 5\\
\Leftrightarrow x = 1 - 5 = - 4
\end{array}\)
2. \(\begin{array}{l}
17 - 3x = - 10\\
\Leftrightarrow 3x = 17 + 10 = 27\\
\Leftrightarrow x = 27:3 = 9
\end{array}\)
3. \(\begin{array}{l}
- 49 - (17 + x) = | - 38|\\
\Leftrightarrow - 49 - (17 + x) = 38\\
\Leftrightarrow 17 + x = - 49 - 38 = - 87\\
\Leftrightarrow x = - 87 - 17 = - 104
\end{array}\)
