## Expanding (9 + x)²

In mathematics, expanding a squared term means multiplying it by itself. In this case, we want to expand (9 + x)².

Here's how we do it:

**(9 + x)² = (9 + x) * (9 + x)**

To multiply these two binomials, we can use the **FOIL** method, which stands for **First, Outer, Inner, Last**.

**First:**Multiply the first terms of each binomial: 9 * 9 =**81****Outer:**Multiply the outer terms of the binomials: 9 * x =**9x****Inner:**Multiply the inner terms of the binomials: x * 9 =**9x****Last:**Multiply the last terms of each binomial: x * x =**x²**

Now we add all the terms together:

**(9 + x)² = 81 + 9x + 9x + x²**

Finally, combine the like terms:

**(9 + x)² = 81 + 18x + x²**

Therefore, the expanded form of (9 + x)² is **81 + 18x + x²**.

## Why is this useful?

Expanding squared terms like this can be useful for solving equations, simplifying expressions, and understanding the relationship between different mathematical concepts. For example, you might encounter this expression when working with quadratic equations, which are equations involving a term with x².