6 = b

b = 6

2 = b

b = 2

s + 6 = 10

-6 - 6

s = 4

s + 6 = 10

+6 + 6

s = 16

z = 7

z = 3

3 = k - 5

+5 + 5

8 = k

k = 8

3 = k - 5

-5 - 5

10 = k

k = 10