Answer:
A. x²-2x-9
Explanation:
If you want to laugh while learning math, then this paragraph is for you. It will show you how to find the perimeter of a weird triangle that has one side equal to x² - 2x - 5. Don't worry, it's not as hard as it sounds. Just follow these steps and you'll be fine.
First, you need to know that the perimeter of a triangle is the sum of the lengths of its three sides. So, to find the perimeter of this triangle, we need to add x, 2 (x - 4), and (x² - 2x - 5). That's easy, right? Just use the distributive property and combine like terms.
P = x + 2 (x - 4) + (x² - 2x - 5) P = x + 2x - 8 + x² - 2x - 5 P = x² + 2x - 9
Wow, look at that! The perimeter is a quadratic expression. How cool is that? But wait, there's more. We need to find the numerical value of the perimeter. To do that, we need to plug in a value of x that is greater than 4. Why greater than 4? Because otherwise the triangle would have negative or zero side lengths, and that's not possible. So let's pick x = 5 and see what happens.
P = (5)² + 2(5) - 9 P = 25 + 10 - 9 P = 26
Ta-da! The perimeter of the triangle is 26 units when x = 5. Isn't that amazing? You can try other values of x that are greater than 4 and see how the perimeter changes. But be careful, don't pick x = -3 or x = 3, because then you'll get P = 0, which means the triangle collapses into a line. And that's not funny at all.