Answer:
There are 7 bricks in the first row of the structure.
Step-by-step explanation:
Our function is b(r) = 7+4(r-1)
In this function, r is the row number.
If we substitute 1 in for r, we have
b(1) = 7+4(1-1) = 7+4(0) = 7+0 = 7
This corresponds with the 7 at the beginning of the function; this means that the 7 in the function is the number of bricks in the first row.