Question

Помогите пожалуйста

Answer 1

$6xy - ( 8 - 4xy) + 5y(1.4 - 2x) = \\ = 6xy - 8 + 4xy + 7y - 10xy = \\ = 7y - 8 = 7 \times 1 \frac{2}{7} - 8 = \frac{7 \times 9}{7} - 8 = \\ = 9 - 8 = 1$