Bài 1: thực hiện các phép tinh A , 180 - 75 : 25 B , 24 . 23 + 3 . 52 C , 136 . 52 + 48 . 136 D , 110 : { 38 - [ -14 + ( -3 )]} Bài 2 : Tìm X : a , 15 + X = 8 b , X - 48 : 3 = 12 c , ( 2X + 4 ) . /-7/ = 70

Bài 1:  Thực hiện phép tính:

\[\begin{array}{l}{\rm{a)}}\,{\rm{180 - 75:25}}\\{\rm{ = 180 - 3}}\\{\rm{ = 177}}\\{\rm{b)}}\,{\rm{24}}{\rm{.23 + 3}}{\rm{.52}}\\{\rm{ = 552 + 156}}\\{\rm{ = 708}}\end{array}\]

\(\begin{array}{l}c)\,136.52 + 48.136\\ = 136.\left( {52 + 48} \right)\\ = 136.100\\ = 13600\end{array}\)

\(\begin{array}{l}d)\,100:\left\{ {38 - \left[ { - 14 + \left( { - 3} \right)} \right]} \right\}\\ = 100:\left( {38 + 14 + 3} \right)\\ = 100:55\\ = \frac{{20}}{{11}}\end{array}\)

Bài 2: Tìm x

\(\begin{array}{l}a)\,15 + x = 8\\ \Leftrightarrow x = 8 - 15\\ \Leftrightarrow x =  - 7\\b)\,x - 48:3 = 12\\ \Leftrightarrow x - 16 = 12\\ \Leftrightarrow x = 12 + 16\\ \Leftrightarrow x = 28\end{array}\)

\(\begin{array}{l}c)\,\left( {2x + 4} \right).\left| { - 7} \right| = 70\\ \Leftrightarrow \left( {2x + 4} \right).7 = 70\\ \Leftrightarrow \left( {2x + 4} \right) = 10\\ \Leftrightarrow 2x = 10 - 4\\ \Leftrightarrow 2x = 6\\ \Leftrightarrow x = 6:2 = 3\end{array}\)