Carl tried to evaluate an expression step by step as shown in the picture. Whitch step did he make a mistake

(5y+11)²

Step-by-step explanation:

The given expression is :

25y²+110y+121

We need to factors of the given expression.

We know that, (11)² = 121

5² = 25

We can write the given expression as :

25y²+110y+121 = (5y)² + 2(5y)(11) +11²

Using identity : (a+b)² = a²+2ab+b²

25y²+110y+121 = (5y+11)²

Hence, the factors of 25y²+110y+121 is (5y+11)².