Question

1) 0,8(3а-14)-0,6(6а-8) а=3 целых 1/13

Answer 1

$0.8(3a-14)-0.6(6a-8) = \ = 2.4a - 11.2 - 3.6a + 4.8 = \ = - 1.2a - 6.4 \ \ a = 3 frac{1}{13} \ \ - 1.2 times 3 frac{1}{13} - 6.4 = - frac{12}{10} times frac{40}{13} - frac{32}{5} = \ = - frac{48}{13} - frac{32}{5} = - frac{(48 times 5 + 32 times 13)}{65} = \ = - frac{240 + 416}{65} = - frac{656}{65} = - 10 frac{6}{65}$