Помогите пожалуйста. 1 и 2 номера

Решите задачу:

$(2 \frac{3}{4} + 2 \frac{1}{5}) \times 16 = 79 \frac{1}{5} \\ 1)2 \frac{3}{4} + 2 \frac{1}{5} = \frac{11}{4} + \frac{11}{5} = \frac{11 \times 5 + 11 \times 4}{20} = \frac{99}{20} = 4 \frac{19}{20} \\ 2)4 \frac{19}{20} \times 16 = \frac{99}{20} \times 16 = \frac{99 \times 16}{20} = \frac{99 \times 4}{5} = \frac{396}{5} = 79 \frac{1}{5}$
$8 + 7x = 9x + 4 \\ 7x - 9x = 4 - 8 \\ - 2x = - 4 \\ x = \frac{ - 4}{ - 2} \\ x = 2$