Answer: There are 7 bricks in the first row of the structure.
Step-by-step explanation:
Given function: [tex]b(r)=7+4(r−1)[/tex] which represents the number of bricks in row r of a structure.
If we put r=1, we get the number of bricks in first row.
[tex]b(1)=7+4(1−1)\\\Rightarrow\ b(1)=7+0\\\Rightarrow\ b=7[/tex]
Therefore, There are 7 bricks in the first row of the structure.
Thus, the value of 7 represents that there are 7 bricks in the first row of the structure.