a) $$23 \cdot 21 + 23 \cdot 79 = 23 \cdot (21 + 79) = 23 \cdot 100 = 2300$$<br><strong>Ответ: 2300</strong><br>б) $$8 \cdot (25 + 7) = 8 \cdot 32 = 256$$<br><strong>Ответ: 256</strong><br>в) $$74 \cdot 238 - 38 \cdot 74 = 74 \cdot (238 - 38) = 74 \cdot 200 = 14800$$<br><strong>Ответ: 14800</strong>