1. **State the problem:** Simplify the expressions and fill in the blanks with the correct numbers. 2. **Part A:** Simplify $19x + 21 - 4x$. - Combine like terms: $19x - 4x = (19 - 4)x = 15x$. - The constant term remains $21$. - So, $19x + 21 - 4x = 15x + 21$. - Therefore, the blanks are $15$ and $21$. 3. **Part B:** Simplify $6.9y - 1.5 - 3.9y$. - Combine like terms: $6.9y - 3.9y = (6.9 - 3.9)y = 3.0y$. - The constant term is $-1.5$. - So, $6.9y - 1.5 - 3.9y = 3.0y - 1.5$. - Therefore, the blanks are $3.0$ and $1.5$. **Final answers:** - Part A: $15 \times x + 21$ - Part B: $3.0 \times y - 1.5$