Find the HCF of 18a2y and 27x2y2, and the sum of the prime factors of 180.

- $18 = 2 \times 3^2$
- $27 = 3^3$

- The common prime factor is 3. The lowest power of 3 is $3^2$.
- HCF of 18 and 27 is $3^2 = 9$.

- For variable 'a', it appears only in $18a^2y$.
- For variable 'x', it appears only in $27x^2y^2$.
- For variable 'y', it appears in both terms. The lowest power of 'y' is $y^1$ (from $18a^2y$).

- $180 = 18 \times 10$
- $18 = 2 \times 9 = 2 \times 3^2$
- $10 = 2 \times 5$

- $180 = (2 \times 3^2) \times (2 \times 5) = 2^2 \times 3^2 \times 5^1$.

- Sum = $2 + 3 + 5 = 10$.

- "The sum of 8 and a certain number": $8 + x$
- "The product of the number and 3": $3x$
- "is equal to": $8 + x = 3x$

- $x = \frac{8}{2}$
- $x = 4$

- 5 becomes 6.