# Solve where x² + y² = r and x + y = 3 (substituting)

In this lesson, we will solve simultaneous equations by substituting a linear equation into a quadratic equation. Examples include quadratics of the form x² + y² = r and x + y = 3, where r can be a square number.

#### Unit quizzes are being retired in August 2023

Why we're removing unit quizzes from the website >
Quiz:

# Intro quiz - Recap from previous lesson

Before we start this lesson, let’s see what you can remember from this topic. Here’s a quick quiz!

Q1.

1/3

Q2.

2/3

Q3.

3/3

#### Unit quizzes are being retired in August 2023

Why we're removing unit quizzes from the website >
Quiz:

# Intro quiz - Recap from previous lesson

Before we start this lesson, let’s see what you can remember from this topic. Here’s a quick quiz!

Q1.

1/3

Q2.

2/3

Q3.

3/3

# Video

Click on the play button to start the video. If your teacher asks you to pause the video and look at the worksheet you should:

• Click "Close Video"
• Click "Next" to view the activity

Your video will re-appear on the next page, and will stay paused in the right place.

# Worksheet

These slides will take you through some tasks for the lesson. If you need to re-play the video, click the ‘Resume Video’ icon. If you are asked to add answers to the slides, first download or print out the worksheet. Once you have finished all the tasks, click ‘Next’ below.

#### Unit quizzes are being retired in August 2023

Why we're removing unit quizzes from the website >
Quiz:

# Solve where 𝒙² + 𝒚² = 𝒓 and 𝒙 + 𝒚 = 𝟑 (substituting)

Don’t worry if you get a question wrong! Forgetting is an important step in learning. We will recap next lesson.

Q1.

1/3

Q2.

2/3

Q3.

3/3

#### Unit quizzes are being retired in August 2023

Why we're removing unit quizzes from the website >
Quiz:

# Solve where 𝒙² + 𝒚² = 𝒓 and 𝒙 + 𝒚 = 𝟑 (substituting)

Don’t worry if you get a question wrong! Forgetting is an important step in learning. We will recap next lesson.

Q1.

1/3

Q2.

2/3

Q3.

3/3

# Lesson summary: Solve where x² + y² = r and x + y = 3 (substituting)

## Time to move!

Did you know that exercise helps your concentration and ability to learn?

For 5 mins...

Move around:
Walk

On the spot:
Chair yoga