ELI5: Explain Like I'm 5

Polynomial evaluation

Okay kiddo, so imagine you have a toy box full of different colored blocks. You can stack these blocks on top of each other to make different shapes, right?

Now let's say I give you a problem: I want you to make a shape using some of the blocks in your box, but the shape has to follow a certain rule. The rule says that you can only use blocks that are yellow or green, and you have to use exactly three of them.

To solve this problem, you would need to go through your toy box and find all the yellow and green blocks. Then you would choose any three of them and stack them together to make your shape.

This is kind of like polynomial evaluation! Instead of blocks, we have numbers and instead of stacking them, we're adding, subtracting, multiplying, and dividing them.

Here's an example: let's say we have a polynomial that looks like this:

3x^2 + 2x + 1

We want to evaluate this polynomial when x is equal to 4. So we start by replacing all the x's in our polynomial with 4:

3(4)^2 + 2(4) + 1

Now we use our knowledge of math to simplify this expression:

3(16) + 8 + 1

48 + 8 + 1

57

So the value of the polynomial 3x^2 + 2x + 1 when x is equal to 4 is 57.

Does that make sense, kiddo? We're just plugging in a number for x and doing some math to find the answer to the problem.