Checking and securing understanding of finding the equation of the line from the graph
I can find the equation of the line from the graph.
Checking and securing understanding of finding the equation of the line from the graph
I can find the equation of the line from the graph.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- Linear equations can be rearranged into the form y = mx + c
- The gradient (m) and the y-intercept (c) can be determined from the graph.
- The amount y changes when x increases by one is the rate of change and called the gradient.
- Where the graph crosses the y-axis is the value of the y-intercept.
- The equation of the line can be written in the form y = mx + c
Keywords
Gradient - The gradient is a measure of how steep a line is. It is calculated by finding the rate of change in the y-direction with respect to the positive x-direction.
Intercept - An intercept is the coordinate where a line or curve meets a given axis.
Common misconception
Writing equations of the form y = mx + c and getting the gradient and y-intercept the wrong way round.
Graphing software can be used to show that adding a constant is a translation of the graph. Remind pupils that the y-intercept is when x is zero which is why it is the constant in the equation. They can substitute x = 0 to check.
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Lesson video
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Starter quiz
6 Questions
constant -
a term that does not vary
coefficient -
the multiplier of a specified variable in a term
gradient -
a measure of how steep a line is
intercept -
the point where a line crosses a specified axis
origin -
the point with coordinates (0, 0)
equation of a straight line -
a relationship which, when plotted, forms a straight line
$$y = 3x − 2$$ -
gradient 3, $$y$$-intercept (0, -2)
$$y = 3x + 2$$ -
gradient 3, $$y$$-intercept (0, 2)
$$y = 2 - 3x$$ -
gradient -3, $$y$$-intercept (0, 2)
$$y = 2x - 3$$ -
gradient 2, $$y$$-intercept (0, -3)
$$y = 3 + 2x$$ -
gradient 2, $$y$$-intercept (0, 3)
$$y = 3 - 2x$$ -
gradient -2, $$y$$-intercept (0, 3)
Exit quiz
6 Questions
A (blue) -
$$y=-{2\over 3}x - 2$$
B (pink) -
$$y=-{3\over 2}x - 2$$
C (black) -
$$y={3\over 2}x $$
D (green) -
$$y={3\over 2}x - 2$$
E (purple) -
$$y={2\over 3}x - 2$$