Answer:
(4x-9)^2.
Explanation:
If you want to simplify 16x^2 - 72x + 81, you can use a cool trick called the square of a binomial rule. This rule says that if you have something like (a + b)^2, you can expand it as a^2 + 2ab + b^2. So, how do we apply this rule to our problem? Well, first we need to find a and b that make our expression look like (a + b)^2. We can do this by noticing that 16x^2 is the same as (4x)^2 and 81 is the same as 9^2. Then we can check that the middle term is -2 times the product of 4x and 9, which is -72x. So we can write our expression as (4x - 9)^2. That's it! We have simplified our expression using the square of a binomial rule.