Question

Упростите и решите выражение : $frac{2}{7}(1,4 a-3frac{1}{2}b)-1,2(frac{5}{6}a-o,5b)$

Answer 1

$frac{2}{7}(frac{14}{10}a-frac{7}{2}b)-frac{12}{10}(frac{5}{6}a-frac{1}{2}b)=$

$frac{2}{7}cdotfrac{14}{10}a-frac{2}{7}cdotfrac{7}{2}b-frac{12}{10}cdotfrac{5}{6}a+frac{12}{10}cdotfrac{1}{2}b=$

$frac{2}{5}a-b-a+frac{3}{5}b=-frac{3}{5}a-frac{2}{5}b=-frac{1}{5}(3a+2b)$