The equation of a straight line graph

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Straight Line Graphs - 24 November, 2009

• Draw a graph from
• coordinates
• an equation

Level 5 7
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Starter What are the co-ordinates?
(-4, -2)
(4, 6)
(-1, 1)
(6, 5)
(5, 3)
(4, -2)
(2, -3)
(3, 2)
(7, 1)
(-2, -4)
(-7, 2)
(1, 5)
(-4, 3)
(-2, -1)
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Drawing a graph from coordinates
Mark the points with the coordinates (1, 2) (2,
3) (3, 4) (4, 5)
Join up the points with a line
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Draw the graph with the coordinates
Draw the graphs for these
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How to draw a graph from an equation The
following is an example of how to draw the graph
of the linear equation y 2x 1
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To draw the graph of y 2x 1 draw a table
like this
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I want to find y 2x 1, so first, you find
the value of the 2x. This means 2 times x so
times each of the x numbers by 2.
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Remember, you want to find y 2x 1 so you add
on 1 to the 2x to find the value of 2x 1
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You have done everything to the x number so now
you have found the y number y 2x 1
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Now, plot the value of x against the value of y
on the graphs axes.
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y 2x 1

• y 2x 3
• y 2x 3
• y 3x 1
• y x 2
• y 3x 2
• y x 4

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Draw the graph of y 6 x
Make a table with x values 0 to 4
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Draw the graph of y 6 x
Find the value of 6 x
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Draw the graph of y 6 x
You have done all that the rule asks so you have
the y value.
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Draw the graph of y 6 x
Now, you can plot the points and draw the graph.
1 . y 4 x 2. y 2 x 3 y 6 2x 4. Y
8 2x