Lesson video

Hi, I'm Miss Davies.

In this lesson, we're going to be drawing quadratic graphs that have an x squared coefficient greater than one.

The table of values can be used to draw a quadratic function.

We're going to fill in this table of values to plot the graph of y is equal to 2x squared subtract 3x add 1.

When x = -3, we do the calculation, 2 multiplied by -3 squared, subtract 3 multiplied by -3 add 1.

This gives the solution for y of 28.

When x = -2 gives us a y value of 15.

When x is -1, y is 6.

When x is zero, this gives a solution for y of one.

This is our constant in the given function.

When x is one, y is zero.

When x is two, the solution for y is three.

When x is 3, the y value is 10.

Now that we've completed our table of values, we can plot these coordinates onto our set of axes.

You can then join these together with a smooth curve.

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.

Remember 2 multiplied by -2 squared is positive eight, and 2 multiplied by -1 squared is positive two.

The constant, positive four, is the y-intercept.

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.

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.

As the x squared coefficient increases, the graphs appear to be becoming narrower.

Here is a question for you to try.

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

Here is the answer.

You can see from the graph that they do reflect in the line, x = 0, which is also known as the y-axis.

That's all for this lesson.

Thanks for watching.