Question

Помогите по алгебре. Решите номер 10. Есть вложение . 20 баллов.

Answer 1

7^(x + 4y) = 7^2

3^(y - 2x) = 3^(-1)

x + 4y = 2 | *2

y - 2x = -1

2x + 8y = 4

-2x + y = -1

9y = 3

x = 2 - 4y

y = 1/3

x = 2 - 4/3 = 6/3 - 4/3 = 2/3

2/3 + 1/3 = 3/3 = 1

Ответ: 1)

Answer 2

${7}^{x + 4y} = {4}^{2} \\ {3}^{y - 2x} = {3}^{ - 1} \\ \\ x + 4y = 2 \\ y - 2x = - 1 \\ \\ x = 2 - 4y \\ y - 2(2 - 4y) = - 1 \\ \\ y - 4 + 8y = - 1 \\ 9y - 4 = - 1 \\ 9y = - 1 + 4 \\ 9y = 3 \\ y = \frac{3}{9} = 1/3 \\ x = 2 - 4y = 2 - \frac{4}{3} = - \frac{2}{5} = 2/3$

2/3+1/3=3/3=1