Worked Example 1
Draw the graph of y = 2x + 1.
Choose easy values of xx = 0, 1 and 2
Work out y for each(0, 1), (1, 3) and (2, 5)
Plot and checkAll three in a row, or recheck before drawing
Join with a ruler and extendExtend the line past the points in both directions
Worked Example 2
Is (4, 9) on the line y = 2x + 1? What about (4, 8)?
Substitute the x value2(4) + 1 = 9
Compare with the y value(4, 9) is on the line
Now test the other(4, 8) is not on the line, sitting one unit below it
Why this test mattersIt works without drawing anything, and it checks a graph you have already drawn.
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