yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

Evaluating expressions like 5x² & ⅓(6)ˣ | 6th grade | Khan Academy


less than 1m read
·Nov 10, 2024

What I want you to do is evaluate the expression 5x squared when x is equal to 3.

Pause this video and have a go at that.

All right, well we just have to think about every place we see an x; we'll now replace it with a 3. So this is going to be equivalent to 5 times, instead of x squared, it's going to be 5 times 3 squared.

And we know, from order of operations, we do the exponents first. That's why I actually put a parenthesis around the 3 squared to just make that clear. And 3 squared is, of course, equal to 9. And 5 times 9 is equal to 45.

Let's do another example that's a little bit different. Let's say I have the expression 1/3 times 6 to the x power, and I want to evaluate it when x is equal to 2.

Pause the video again and see if you can work that out.

Well, once again, everywhere where we see an x, we'll replace that with a 2. So this is going to be the same thing as 1/3 times 6 squared, where we saw the x, we now replace that with a 2.

And so this is going to be equal to, we do the exponent first, order of operations, so it's going to be 1/3 times 6 squared is 36, and one third of 36 is equal to 12. And we're done.

More Articles

View All
Millionaire Financial Advice For 18-35 Year Olds | Millennial Money
What’s up you guys, it’s Graham here! So for those who have not seen my second channel, The Graham Stefan Show, I regularly review a series by CNBC which covers the common everyday financial habits and financial mistakes of millennials, which is appropria…
How to become a strong negotiator!
Best place to learn your negotiating skills is with your boyfriend, girlfriend, husband, wife, your kids, your parents. That’s the place you fight like hell, and then you make up right after that. But at least, hopefully, you’ve learned something about it…
Introduction to dividing by 2 digits
What we’re going to do in this video is start trying to divide by two-digit numbers. As we’ll see, this is a super important skill that a lot of the rest of mathematics will build off of. But it’s also interesting because it’s a bit of an art. So let’s ju…
Your New Sidekick (Notepad!)
This is the Sidekick Notepad. Your new desk capture companion, here to help you stay organized and look good, like a good sidekick should. Slimly sized to sit between you and your keyboard, as tested by thousands of users on all their different desktops, …
Long run supply curve in constant cost perfectly competitive markets | Microeconomics | Khan Academy
[Man] Alright, now let’s dig a little bit more into analyzing perfectly competitive markets, and in particular, we’re gonna focus on the long run. Remember, the long run is the time span where firms can enter and exit the market. Or, another way to think …
How UV Causes Cancer and Aging
Recently, I made a video about what the world looks like in the ultraviolet. Some things look the same, but generally, it’s hazier. Sometimes light and dark are flipped, skin looks blotchier, and fake teeth stand out. Whoa! Smile for me. Oh my goodness, …