To factor perfect square trinomials, you need to find a math expression that looks like this:

• $a^2 + 2ab + b^2$
• or $a^2 - 2ab + b^2$.

These can be rewritten as:

• $(a + b)^2$
• or $(a - b)^2$.

Let’s see how this works with some examples.

Example 1:

For the expression $x^2 + 6x + 9$:

• First, identify $a$ and $b$. In this case, $a = x$ and $b = 3$.
• Now, it can be factored to $(x + 3)^2$.

Example 2:

For the expression $x^2 - 4x + 4$:

• Here, $a = x$ and $b = 2$.
• This part factors to $(x - 2)^2$.

So, remember! Just find $a$ and $b$, and use these simple formulas!