Lesson video

Hi, I'm Miss Davies.

In today's lesson, we're going to be simplifying expressions by collecting like terms. Like terms are part of an expression that share a common letter and/or power.

If we look at these terms, which ones are like terms? These are all like terms as they contain the letter a.

These are like terms as they are both a squared terms. a cubed is not a like term to a squared or a as the power is different.

Three b is not a like term to any of those as the letter is different.

Let's have a look at this expression.

How many different terms can you see? We've got three e terms. We've then got two f terms. We've also got an ef term and an f squared term.

Here's some questions for you to try.

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Here is the answers.

Like terms share a comment letter and power.

x squared and x cubed are not like terms because the powers are different.

Eight ce and four ec, are all like terms because ce is equivalent to ec.

We can only add or subtract terms if they are like terms. Five a plus seven a is equivalent to 12a.

Five a add seven a is not equivalent to 12ab.

Seven a add 12a is equivalent to 19a.

Because the variables are the same, so it's just a case of adding the coefficients.

The coefficients are the number that the variable has been multiplied by.

In this case, seven and 12.

92d subtract four d is equivalent to 88d.

Nine y subtract 15y is equivalent to negative six y.

0.

7P add 0.

01P is equivalent to 0.

71p.

Here is some questions for you to try.

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Here are the answers.

These expressions only contain like terms. So it's simply a case of adding the coefficients.

Looking at this first example, we have two different variables, a and b.

First, we're going to separate the terms. We've got four a, positive two b, positive three a.

Our like terms are four a and three a.

These sum to make seven a, and then we've got two b as well.

With this next example, we've again, got two terms. We'll separate the terms and underline our like terms in the same style.

Five c add two c is seven c.

Four d add three d is seven d.

Five c add four d add two c add three d is equivalent to seven c add seven d.

with our next example, we've got three b add seven q, subtract three q add two p.

Three p add two p is equivalent to five p.

Seven q subtract three q is equivalent to four q.

In this next example, we've got negative five r add four s, subtract two r add three s add five r.

Our r terms sum to make negative two r and our s terms sum to make seven s.

We could also write this as seven s subtract two r.

In this final example, we've got two different terms. We've got seven t and negative two t as well as five t squared and t squared.

Seven t subtract two t is five t and five t squared add two t squared is six t squared.

This could not be simplified any further as t squared and t are different terms Here's some questions for you to try.

Pause the video to complete your task and resume once you're finished.

Here are the answers.

Make sure you've only added or subtracted the like terms in each expression.

Here's some questions for you to try.

pause the video to complete your task and resume once you're finished.

Here are the answers.

For question four, there's really common mistakes that people make.

So make sure that you understand why they're wrong.

For question five, to simplify the expression, you need to make sure that you add the same denominator, for each pair of terms. That's all for this lesson.

Thanks for watching.