Решите уравнение: 1) 2x = 15-x; 2) 10x+21=7x;

Решение:

1. 1) \( 2x = 15 - x \)
   \( 2x + x = 15 \)
   \( 3x = 15 \)
   \( x = \frac{15}{3} \)
   \( x = 5 \)
2. 2) \( 10x + 21 = 7x \)
   \( 10x - 7x = -21 \)
   \( 3x = -21 \)
   \( x = \frac{-21}{3} \)
   \( x = -7 \)

Ответ: 1) \( x = 5 \); 2) \( x = -7 \).