(1,0 điểm) Tính hợp lí các biểu thức sau: a) ( 179 + 32 − 25 ) − ( 179 − 75 + 32 ) . b) − 138 ⋅ 2 + 125 ⋅ 3 − ( − 138 ⋅ 2 ) + 75 ⋅ 3.

a) \(\left( {179 + 32 - 25} \right) - \left( {179 - 75 + 32} \right)\)

\( = 179 + 32 - 25 - 179 + 75 - 32\)

\( = \left( {179 - 179} \right) + \left( {32 - 32} \right) + \left( { - 25 + 75} \right)\)

\( = 0 + 0 + 50\)

\( = 50.\)

b) \( - 138 \cdot 2 + 125 \cdot 3 - \left( { - 138 \cdot 2} \right) + 75 \cdot 3\)

\( = \left[ { - 138 \cdot 2 - \left( { - 138 \cdot 2} \right)} \right] + \left( {125 \cdot 3 + 75 \cdot 3} \right)\)

\( = 0 + 3 \cdot \left( {125 + 75} \right)\)

\( = 0 + 3 \cdot 200\)

\( = 0 + 600\)

\( = 600.\)