12+z:8=21

To solve the equation \( 12 + \frac{z}{8} = 21 \), follow these steps:

1. Isolate \(\frac{z}{8}\) by subtracting 12 from both sides of the equation:

   \[ \frac{z}{8} = 21 - 12 \]

   \[ \frac{z}{8} = 9 \]

2. Next, multiply both sides of the equation by 8 to solve for \(z\):

   \[ z = 9 \times 8 \]

   \[ z = 72 \]

Thus, \(z = 72\).