Lesson video

Hello, my name's Miss Parnham.

In this lesson, we're going to learn how to solve one-step equations.

Let's start by solving this equation.

The bar model may help you understand the steps to isolate the unknown, so we have a solution.

In order to get a on it own, we need to find the inverse for adding 11, which is subtracting 11, and then do this to both sides of the equation.

a equals 13.

Now let's solve four b equals negative 48.

The inverse of multiplying by four is divided by four.

So we do that to both sides of the equation.

So b equals negative 12.

Sometimes, we have to form and solve an equation to solve a problem.

In this case, we have an equilateral triangle with a perimeter c.

So c divided by three, 'cause it's got three sides, equals nine.

The inverse of divided by three is multiplying by three.

So c equals 27.

Here are some questions for you to try.

Pause the video to complete the task and restart the video when you're finished.

Here are the answers.

In question two, we had an example involving vertically opposite angles.

As these are equal, we form an equation of five t equals 65, then solve to find that t equals 13.

Here are some further questions for you to try.

Pause the video to complete the task and restart the video when you're finished.

Here are the answers.

In question four, you'll notice the Amir should have divided by negative eight.

So the solution for e is negative six.

Solving equations involving decimals works in just the same way as for integers.

Let's subtract 3.

4 from both sides of this equation.

So d equals 4.

76.

Here we have three e equals negative 7.

56.

Let's divide both sides by three.

So e equals negative 2.

52.

Let's have a look at this problem.

Rosie has some money that she shares equally between herself and four friends.

It's really important that you remember to include Rosie in this problem.

So they each get one pound 17.

Form and solve an equation to discover how much money Rosie starts with.

f divided by five, because that's Rosie plus four friends, equals 1.

17.

Multiplying both sides of the equation by five, means that f equals 5.

85.

So Rosie has five pounds, 85 to begin with.

Here are some questions for you to try.

Pause the video to complete the task and restart the video when you're finished.

Here are the answers.

In question six, if you wrote three and a quarter grammes, then that's also right.

Here are some further questions for you to try.

Pause the video to complete the task and restart the video when you're finished.

Here are the answers.

In question eight, it doesn't matter whether you prefer to work with fractions or decimals.

If you did use the former, then a solution of negative four and a quarter is just as valid.

That's all for this lesson.

Thanks for watching.