Question

5а +2в при а= 7/15 в= -5/6

Answer 1

$5a + 2b = 5 \times \frac{7}{15} + 2 \times ( - \frac{5}{6} ) = 5 \times \frac{7}{15} - 2 \times \frac{5}{6} = \frac{5 \times 7}{15} - \frac{2 \times 5}{6} = \frac{5 \times 7}{5 \times 3} - \frac{2 \times 5}{2 \times 3} = \frac{7}{3} - \frac{5}{3} = \frac{7 - 5}{3} = \frac{2}{3}$