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Combining like terms with distribution

Learn to expand and simplify an expression like 3(5x+6) + (7x+2)*4.

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Video transcript

- [Voiceover] So I have an expression here. Three times the entire expression 5x plus six, and then plus the expression 7x plus two and all of that times four. And what I encourage you to do is pause this video and see if you can simplify this expression. And I'll give you a hint. You're gonna have to do some distribution and then some combining of like terms. All right, now I'm assuming you've had a go at it. Now let's work through this together. So as I mentioned, when I see this three times the entire expression 5x plus six, I want to distribute that three. So I want to multiply that three times 5x and that three times the six. So three times 5x, well if I have five Xs and I have three times that, I'm gonna have 15 Xs. And then three times six is 18. So this part of the expression we have now simplified to 15x plus 18. Now let's do the next part. So here I have this larger expression written before this four but I wanna do the same thing. I just wanna distribute the four. It doesn't matter whether I'm multiplying, if I have the three or if I have the number on the left side or the right side, so let's distribute this four. I wanna do four times 7x and I wanna do four times two. Four times 7x, well that's going to be 28x, 28x. And then four times two is going to be eight. So we're almost there. This part of our expression has simplified to 28x plus eight and now we can combine similar terms. So we have 15 Xs, and then we can add that to 28 Xs. Let me do this in a different color. If I have 15 of something and I add 28 of something of that same something to it, well then I'm gonna have what, 43 Xs. So 43 Xs. 15x plus 28 Xs, I added the coefficients there, that's gonna be 43 Xs. And then 18 plus eight. Hey, let me do this in a new color. So 18 plus eight is going to be 26. And we're done. We've simplified this longer expression. We did some distribution then we combined some terms to get 43x plus 26.