Year 9 Simultaneous Equations Worksheet — Level 3 — Practice Set 2 — Answers
Answer sheet with worked solutions for the Year 9 simultaneous equations worksheet.
Year 9 Simultaneous Equations Worksheet — Level 3 — Practice Set 2 — Answers
Solve each pair of equations. Check your solution satisfies both equations.
1.Solve simultaneously: 2x + 2y = 22 and 3x − 5y = −23
Answer: x = 4, y = 7
- Multiply equation 1 by 3 and equation 2 by 2 to match the x coefficients
- 6x + 6y = 66 and 6x − 10y = −46
- Subtract: 16y = 112, so y = 7
- Substitute back: x = 4
2.Solve simultaneously: 4x + y = 34 and 5x + 5y = 65
Answer: x = 7, y = 6
- Multiply equation 1 by 5 and equation 2 by 4 to match the x coefficients
- 20x + 5y = 170 and 20x + 20y = 260
- Subtract: −15y = −90, so y = 6
- Substitute back: x = 7
3.Solve simultaneously: 2x + 3y = 38 and 4x + 4y = 60
Answer: x = 7, y = 8
- Multiply equation 1 by 4 and equation 2 by 2 to match the x coefficients
- 8x + 12y = 152 and 8x + 8y = 120
- Subtract: 4y = 32, so y = 8
- Substitute back: x = 7
4.Solve simultaneously: 4x + 2y = −4 and 3x − 3y = −12
Answer: x = −2, y = 2
- Multiply equation 1 by 3 and equation 2 by 4 to match the x coefficients
- 12x + 6y = −12 and 12x − 12y = −48
- Subtract: 18y = 36, so y = 2
- Substitute back: x = −2
5.Solve simultaneously: 2x + 3y = 13 and 4x − 5y = −51
Answer: x = −4, y = 7
- Multiply equation 1 by 4 and equation 2 by 2 to match the x coefficients
- 8x + 12y = 52 and 8x − 10y = −102
- Subtract: 22y = 154, so y = 7
- Substitute back: x = −4
6.Solve simultaneously: 2x + 4y = −2 and 4x + 5y = 8
Answer: x = 7, y = −4
- Multiply equation 1 by 4 and equation 2 by 2 to match the x coefficients
- 8x + 16y = −8 and 8x + 10y = 16
- Subtract: 6y = −24, so y = −4
- Substitute back: x = 7
7.Solve simultaneously: 3x − 2y = 33 and 5x + 5y = 5
Answer: x = 7, y = −6
- Multiply equation 1 by 5 and equation 2 by 3 to match the x coefficients
- 15x − 10y = 165 and 15x + 15y = 15
- Subtract: −25y = 150, so y = −6
- Substitute back: x = 7
8.Solve simultaneously: 3x − 4y = −43 and 3x + y = −8
Answer: x = −5, y = 7
- Subtract equation 2 from equation 1: −5y = −35
- y = 7
- Substitute into equation 1: 3x − 28 = −43, so x = −5
Marking tips
- Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
- For open-ended tasks, use the success criteria as a checklist rather than looking for one "right" answer.
- Celebrate what went well first, then pick one thing to work on next.