Foundation and Higher · plotting a line

Plot a line from
its equation.
Table, points, ruler.

most lost marks are
in the negatives

the skill underneath —

Substitute

swap x for a number

then work out y

step 1 of 4

Fill in the table

1. Put each x into y = 2x − 1.

2. x = 3 gives 2 × 3 − 1 = 5.

3. x = −2 gives 2 × (−2) − 1 = −5.

✓ The y-values go up by 2 each time

step 2 of 4

Plot the points

1. Each column is a coordinate (x, y).

2. Across first, then up or down.

✓ They should line up.
If one does not, recheck it

step 3 of 4

Draw the line

1. Join the points with a ruler.

2. Carry on past the end points.

✓ Label it y = 2x − 1

step 4 of 4

Check it

1. It crosses the y-axis at −1: that is c.

2. 1 across, 2 up: gradient 2: that is m.

✓ Both match y = 2x − 1

plotting a line —

Table

substitute each x

Plot

across, then up or down

Draw

ruler, right across the grid

Negative x? Use brackets:
2 × (−2) = −4.

The
Maths Habit

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