Question

72а+42аб-6ас-12а-7б +с якщо а=5/6б=2/7с=-1

Answer 1

$72\cdot\frac{5}{6}+42\cdot\frac{5}{6}\cdot\frac{2}{7}-6\cdot\frac{5}{6}\cdot(-1)-12\cdot\frac{5}{6}-7\frac{2}{7}+(-1)=12\cdot5+7\cdot5\cdot\frac{2}{7}+5-2\cdot5-7\frac{2}{7}-1=60+5\cdot2+5-2\cdot5-7\frac{2}{7}-1=64-\frac{51}{7}=\frac{397}{7}=56,7$