Answer:
10. 4x
11. r - 7
Explanation:
10.
"a number" refers to any number. Since we don't know the specific number, we use x, a variable, to represent "a number." Then we multiply x by 4.
Answer: 4x
11.
When you decrease a number by 7, you are subtracting 7 from that number.
Answer: r - 7