To solve these equations:

1) 40 - 4.9x = 4.72:

Subtract 40 from both sides:

-4.9x = -35.28

Divide by -4.9 to solve for x:

x = 7.2

2) $z-1.2$ / 0.4 = 2.7:

Divide 2.7 by 0.4:

z - 1.2 = 6.75

Add 1.2 to both sides:

z = 7.95

3) 3.5p - p = 9.8:

Combine like terms:

2.5p = 9.8

Divide by 2.5 to solve for p:

p = 3.92

4) $12.4-s$ / 4.99 = 0.75:

Multiply both sides by 4.99:

12.4 - s = 3.7425

Subtract 12.4 from both sides:

-s = -8.6575

Divide by -1 to solve for s:

s = 8.6575

5) 8k - 7.95k = 0.6585:

Combine like terms:

0.05k = 0.6585

Divide by 0.05 to solve for k:

k = 13.17