Question

ПОМОГИТЕЕЕ!!! Нужно довести тутожность​

Answer 1

$a - (4a - 11) + (9 - 2a) = 20 - 5a \\ a - 4a + 11 + 9 - 2a = 20 - 5a \\ 20 - 5a = 20 - 5a$

$6(3b - 4) - 5(3b - 11) + 2 = 3b + 33 \\ 18b - 24 - 15b + 55 + 2 = 3b + 33 \\ 3b + 33 = 3b + 33$

$10 - 9(c - \frac{2}{3} ) + 7c - 16 = - 2c \\ 10 - 9c + \frac{9 \times 2}{3} + 7c - 16 = - 2c \\ - 6 + 6 - 2c = - 2c \\ - 2c = - 2c$