Question

$(5y-1)^2$

Explanation:

Step1: Recall square of difference formula

The formula is $(a-b)^2 = a^2 - 2ab + b^2$

Step2: Substitute $a=5y$, $b=1$

$$\begin{align*} (5y-1)^2&=(5y)^2 - 2(5y)(1) + 1^2 \end{align*}$$

Step3: Calculate each term

$$\begin{align*} (5y)^2&=25y^2, \quad 2(5y)(1)=10y, \quad 1^2=1 \end{align*}$$

Step4: Combine the terms

$$\begin{align*} (5y-1)^2&=25y^2 - 10y + 1 \end{align*}$$

Answer:

$25y^2 - 10y + 1$