Solve for z.
12 = 15 ( z - 1/5 )

1=z

Step-by-step explanation:

Multiply 15 to the parenthesis.  

12=15z-15/5

12=15z-3

Add 3 to both sides

15=15z

Simplify

1=z

Strategy 1: To transport 1/42 to the other side, take a reciprocal of it and becomes 42. To get the value x, this 42 is multiplied by 3/7. That is
x = 42*(3/7) = 126/7 = 18

Strategy 2: To cancel 1/42 beside x, you multiply by 42 on both sides.
[(1/42)*x]*42 = 42*(3/7)
x = 126/7
x = 18