I need an equation example with an unknown factor?

I want to buy eight bracelets, I don't know how much each bracelet costs, but the final cost will be $39.67.

The equation would look like this:

8 x c = 39.67

Where c equals cost.

To find the answer I would do the following:

8 x c = 39.67

c = 39.67 / 8

c ≈ 4.95

Each bracelet costs about $4.95.

Lets say, I bought 3 cakes in the store and I spent $300, how much does a cake cost?

The equation representing that situation is the following, calling x the cake cost, our unknown factor:

3x = 300

we can solve this equation by dividing all equation by 3:

x = 100

therefore each cake costs $100