Chapter 1 Practice Paper: Linear Graphs and Simultaneous Linear Equations — mark scheme
Secondary 2 · Lower Secondary Mathematics (G2 / G3)
Mark scheme
Linear Graphs and Simultaneous Linear Equations
Chapter 1 Practice Paper · Maximum mark: 30
Notes for markers
- Award one mark for each point marked [1], up to the marks shown for the part.
- Accept answers worded differently that show the same understanding.
- Units are required where the answer line shows one. ecf: allow an error carried forward.
Section A: Multiple-choice questions[10 marks]
| Question | Answer | |
|---|---|---|
| 1 | CRewriting as y = −2x + 5 shows the coefficient of x, −2, is the gradient. | 1 |
| 2 | AAt x = 1 the equation gives y = 4, so (1, 4) satisfies it. | 1 |
| 3 | DGradient 2 gives the 2x term, and the point (0, −3) fixes c = −3. | 1 |
| 4 | BOn the x-axis y = 0, so 2x = 12 and x = 6. | 1 |
| 5 | CSame gradient 2 but different intercepts: the lines never meet. | 1 |
| 6 | A3x = x + 2 gives x = 1, and then y = 3. | 1 |
| 7 | DAdding the equations gives 2x = 12, so x = 6. | 1 |
| 8 | BSubstituting x = 3: 6 + y = 8, so y = 2. | 1 |
| 9 | CThe crossing point is the one pair of coordinates that satisfies both equations. | 1 |
| 10 | ASubtracting the receipts removes the files: two notebooks cost 13 − 7 = $6, so one is $3. | 1 |
Section B: Structured questions[20 marks]
| Question | Answer and marking points | Marks |
|---|---|---|
| 1(a) | y = −1, 1, 5, 7 (with the given 3 at x = 0).
| 2 |
| 1(b) | Gradient 2; y-intercept (0, 3).
| 2 |
| 1(c) | Yes: when x = 4, y = 8 + 3 = 11, matching the point.
| 1 |
| Total for Question 1 | 5 | |
| 2(a) | Both equations contain exactly one x, so subtracting gives x − x = 0.
| 1 |
| 2(b) | (x + 2y) − (x − y) = 11 − 2 gives 3y = 9, so y = 3.
| 2 |
| 2(c) | x − 3 = 2 gives x = 5. Check: 5 + 2(3) = 11 ✓. Solution (5, 3).
| 2 |
| Total for Question 2 | 5 | |
| 3(a) | x + 2(3x − 1) = 12, which expands to x + 6x − 2 = 12.
| 2 |
| 3(b) | 7x = 14, so x = 2. [1] | 1 |
| 3(c) | y = 3(2) − 1 = 5; the solution is (2, 5).
| 2 |
| Total for Question 3 | 5 | |
| 4(a) | 3s + 2b = 19 and s + 2b = 9, where s is the scooter price and b the bumper-car price.
| 2 |
| 4(b) | Subtracting: 2s = 10, so s = 5; then 5 + 2b = 9 gives b = 2.
| 2 |
| 4(c) | 4(5) + 2 = $22 [1] | 1 |
| Total for Question 4 | 5 |
— End of mark scheme —