what is the linear equation in y=mx+b for this pattern

In the given figure the number of block are increase by 2
So, The expression show an series of Airthmetic sequence where nth term is express as:
[tex]a_n=a_1+(n-1)d[/tex]So, the rate of change in teh system is 2
Slope =2
The expresion in the y = mx +b
Here we get m = 2
So,
equation will be :
[tex]\begin{gathered} y=\text{ 1+(x-1)}2 \\ y\text{ = (x-1)2 +1} \end{gathered}[/tex]where x respresnt the number of pattern and y represnt the number of blocks.
Answer : Expression : y = 2(x-1) + 1