Here is a pattern of houses with matchsticks:

Write the general rule for this pattern.
One house is made of 6 matchsticks i.e. 6 × 1
Two houses are made of 12 matchsticks i.e. 6 × 2
Three houses are made of 18 matchsticks i.e. 6 × 3
∴ Rule is 6n where n represents the number of houses.