Algebra (all content)
- Adding polynomials
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- Add & subtract polynomials
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- Adding and subtracting polynomials review
Sal simplifies (5x² + 8x - 3) + (2x² - 7x + 13x). Created by Sal Khan and Monterey Institute for Technology and Education.
We're asked to simplify 5x squared plus 8x minus 3 plus 2x squared minus 7x plus 13x. So really, all we have to do is we have to combine like terms-- terms that have x raised to the same power. And the first thing we can do, we can actually get rid of these parentheses right here, because we have this whole expression, and then we're adding it to this whole expression. The parentheses really don't change our order of operations here. So let me just rewrite it once without the parentheses. So we have 5x squared plus 8x minus 3 plus 2x squared. If this was a minus then we'd have to distribute the negative sign, but it's not. So plus 2x squared minus 7x plus 13x. Now let's just look at the different terms that have different degrees of x. Let's start with the x squared terms. So you have a 5x squared term here and you have a 2x squared term right there. So 5 of something plus 2 of that same something is going to be 7 of that something. So that's going to be 7x squared. And then let's look at the x terms here. So we have an 8x right there. We have a minus 7x. And then we have a plus 13x. So if you have 8 of something minus 7 of something, you're just going to have 1 of that something. And then if you add 14 of that something more, you're going to 15. So this is going to be plus 15x. 8x minus 7x-- oh, sorry. You're going to have 14x. 8 minus 7 is 1 plus 13 is 14. Plus 14x. That's these three terms. 8x minus 7x plus 13x. And then finally, you have a negative 3-- or minus 3, depending on how you want to view it. And that's the only constant term. You could say it's x times x to the 0. But it's a constant term. It's not be multiplied by x. And that's the only one there, so minus 3. And we've simplified it as far as we can go. We are done.