Lesson video

Hi, I'm Miss Davies.

In this lesson, we're going to be using graphs to solve equations, including solving simultaneous equations.

The graphs that are shown are the line y equals two x subtract four and y equals two.

We're going to circle the point where the graphs intersect.

This means the point where the lines cross over, which is here.

The coordinates of this point are three, two.

The solution, it's the equation two equals two x subtract four, is that x is equal to three, as this is the x-coordinate of this point.

Here are some questions for you to try.

Pause the video to complete your task, and resume once you're finished, Here are the answers.

The two lines cross over at the point two, 12, because x is the only unknown in the equation in part c.

The solution is x equals two.

Here are some questions for you to try.

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

Here are the answers.

Y equals negative two x plus eight has a gradient of negative two and a y-intercept of eight.

The lines y equals negative two x plus eight, and y equals five crossover at the point 1.

5, five.

This means that the solution is x equals 1.

5.

The graphs of y equals 2/3 x add 2/3 and y equals 10 x subtract 18 are shown.

Circle the point where the graphs intersect.

This is here.

The coordinate of this point are two, two.

To solve the simultaneous equations, we are finding the point in which the graphs intersect.

So the solution to the pair of simultaneous equations, is x is equal two, y is equal to two.

We're going to draw the graph of the equations y equals x at one and y equal to three subtract x.

This is the graph of y equals x at one.

And this is the graph of y is equal to three subtract x.

We're going to use this graph to solve the simultaneous equations.

To solve a pair of simultaneous equations, we are looking for the point where the two lines intersect.

This is here.

This coordinate is one, two.

The solution to the simultaneous equation is x is equal to one, and y is equal to two.

Here are some questions for you to try.

Pause the video to complete your task and resume once you're finished, Here are the answers.

These two lines crossover at the point three, one.

This means that the solution to the pair of simultaneous equations is x equals three, y equals one.

Here are some questions for you to try.

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

Here are the answers.

These two lines should have crossed over at the point one, two, which means that the solution to the simultaneous equations is x equals one, y equals two.

That was all for this lesson.

Thanks for watching.