1) a) 3x + 7 = 0; б) 13 - 100x = 0;

Решение:

1. 1) а)
   1. \( 3x + 7 = 0 \)
   2. \( 3x = -7 \)
   3. \( x = -\frac{7}{3} \)
2. 1) б)
   1. \( 13 - 100x = 0 \)
   2. \( 13 = 100x \)
   3. \( x = \frac{13}{100} \)

Ответ: 1) а) \( x = -\frac{7}{3} \); 1) б) \( x = \frac{13}{100} \).