21 19x + 700.7 = 336 9x + 7x = 336;7 9x+7x=48

Решение:

1. 19x + 700.7 = 336

   19x = 336 - 700.7

   19x = -364.7

   $$x = \frac{-364.7}{19}$$

   $$x = -19.19$$

2. 9x + 7x = 336 : 7

   16x = 48

   $$x = \frac{48}{16}$$

   x = 3

3. 9x + 7x = 48

   16x = 48

   $$x = \frac{48}{16}$$

   x = 3

Ответ: x = -19.19; x = 3; x = 3