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

Manipulating expressions using structure | Mathematics I | High School Math | Khan Academy


less than 1m read
·Nov 11, 2024

So we're told that suppose a plus b is equal to zero. Which of these expressions equal a * b? And like always, pause the video and see if you can figure it out. These are actually pretty fun problems!

All right, so let's see if we can do a little bit of manipulation. So we’re told that a plus b is equal to zero. So if we subtract b from both sides, we would get... so if I subtract b from both sides, I would get a is equal to negative b.

So what is a * b equal to? So a * b, well, I could write this a few ways. I could substitute the a with a negative b since we know a is equal to negative b, in which case a * b would be negative b * b, which is equal to negative b².

Another option is I could... I could... I could instead of saying a is equal to b, I could say that b is equal to a if we multiplied both sides by 1. So b is equal to a, and so instead of substituting a, I could substitute b with a.

And so this expression would be a * a, which is equal to a². So let's see which of these choices are... There's a negative b², but not negative a². So we see the negative a² right over there. So I'm feeling good! I'm feeling good about that choice.

More Articles

View All
The Role of Role Models | StarTalk
[Music] It’s often said that it’s easier to be something if you can see it; if you can imagine yourself in that position. Role models have always played an important role in that. Role models have that role. I have a slightly contrarian view of role mode…
How to Perform a Donut | Science of Stupid: Ridiculous Fails
There are three kinds of donuts: sugary ring donuts, sugary jelly-filled donuts, and then there are the ones that are really bad for your health. These ones. Well, I can see why people pay money to watch this. But take any friction fighting hijinks to the…
The Most Important Decision is Getting Started – Laura Behrens Wu
Hello, I’m Carolyn Levy, a partner at Y Combinator, and I’m delighted to introduce our next speaker, Laura Behrens, who is the founder and CEO of Shippo. Shippo makes it easier and more affordable for e-commerce companies to ship goods. Laura and her co-f…
You Can Do More Than You Think | The Growth Mindset
Probably most people know the story about the turtle and the rabbit, in which the rabbit laughed at the turtle because of his slowness. But to his surprise, the turtle challenged the rabbit to a race. Initially, the rabbit thought the turtle was joking, b…
Understanding scatterplots | Representing data | Grade 5 (TX TEKS) | Khan Academy
We’re told the table below shows the ages of six people and the number of pets they own. So, this row is age of people, and then the second row is the number of pets. So the person who’s nine years old owned four pets. The person who’s eight years old ow…
Canceling zeros when dividing | Math | 4th grade | Khan Academy
Let’s solve 350 divided by 50. So one way to think about this is if we had 350 of something, let’s say something delicious like brownies. If we had 350 brownies and we were dividing them into groups of 50, how many groups of 50 could we get? Well, one ide…