Answer:
z = 1 i hope this helps! :)
Explanation:
given 12 = 15(z - 1/5)
distribute the 15 to both the z and the - 1/5
12 = 15z - 3
add 3 to both sides
15 = 15z
divide both sides by 15
1 = z
flip the equation around so the variable is on the left
z = 1