Решите пропорции: a) x-2/3 = x+4/7 в) 3-x/2 = x+1/5 б) 2x-1/5 = x+3/4 г) x/4 = x-3/2

Решим пропорции:

1. a) $$\frac{x-2}{3} = \frac{x+4}{7}$$

   $$7(x-2) = 3(x+4)$$

   $$7x - 14 = 3x + 12$$

   $$7x - 3x = 12 + 14$$

   $$4x = 26$$

   $$x = \frac{26}{4} = \frac{13}{2} = 6.5$$

2. б) $$\frac{2x-1}{5} = \frac{x+3}{4}$$

   $$4(2x-1) = 5(x+3)$$

   $$8x - 4 = 5x + 15$$

   $$8x - 5x = 15 + 4$$

   $$3x = 19$$

   $$x = \frac{19}{3} = 6\frac{1}{3}$$

3. в) $$\frac{3-x}{2} = \frac{x+1}{5}$$

   $$5(3-x) = 2(x+1)$$

   $$15 - 5x = 2x + 2$$

   $$2x + 5x = 15 - 2$$

   $$7x = 13$$

   $$x = \frac{13}{7} = 1\frac{6}{7}$$

4. г) $$\frac{x}{4} = \frac{x-3}{2}$$

   $$2x = 4(x-3)$$

   $$2x = 4x - 12$$

   $$4x - 2x = 12$$

   $$2x = 12$$

   $$x = 6$$

Ответ: а) 6.5; б) 6 1/3; в) 1 6/7; г) 6