1) (5x - 15)/2 = 5
2) 20/(x + 9) = 2
3) 35/(9 - 2x) = 5
4) (1/4x - 5)/10 = 1/2
5) 10/3 : (x - 40) = 1/3

1) (5x - 15)/2 = 5

5x - 15 = 2 * 5

5x - 15 = 10

5x = 10 + 15

5x = 25

x = 5

2) 20/(x + 9) = 2

x + 9 = 20 / 2

x = 10 - 9

x = 1

3) 35/(9 - 2x) = 5

9 - 2x = 35/5

-2x = 7 - 9

2x = 2

x = 1

4) (1/4x - 5)/10 = 1/2

1/4x - 5 = 1/2 * 10

1/4x = 10

x = 10 * 4

x = 40

5) 10/3 : (x - 40) = 1/3

10/3 = 1/3 (x - 40)

10/3 = 1/3x - 40/3

1/3x = 50/3

x = 50/3 : 1/3

x = 50