Tables of Values & Plotting y = mx + c
Completing tables of values and plotting straight-line graphs across 4 quadrants
Key Method & Revision Notes
- To draw a straight-line graph such as $y = 2x - 1$ across a grid from $x = -2$ to $x = 3$:
- $x$ — $-2$ — $-1$ — $0$ — $1$ — $2$ — $3$
- $y$ — $-5$ — $-3$ — $-1$ — $1$ — $3$ — $5$
- 3 Steps for Full Marks:
- 1. Start with positive $x$ values ($0, 1, 2, 3$) — they are easiest! Notice the $y$-values step up by the gradient ($+2$) each time.
- 2. Plot each $(x, y)$ pair with a neat cross ($\times$).
- 3. Join with a single ruled straight line right across the grid — if one point doesn't sit on the straight line, re-check your arithmetic for that point!
Worked Example
Complete the table of values for $y = 3x - 2$ for $x = -1, 0, 1, 2$.
Start from $x = 0$: $y = -2$.
At $x = 1$: $y = 3(1) - 2 = 1$.
At $x = 2$: $y = 3(2) - 2 = 4$.
At $x = -1$: $y = 3(-1) - 2 = -5$.
Plot $(-1, -5), (0, -2), (1, 1), (2, 4)$ and join with a ruler.
y = -5, -2, 1, 4
Ready to test this skill? Use the interactive tool at the top of the page to practise 10 self-marking exam-style questions (30 questions loaded in this topic module).