Year 12 Simultaneous Equations Worksheet — Level 2 — Practice Set 2 — Answers
Answer sheet with worked solutions for the Year 12 simultaneous equations worksheet.
Year 12 Simultaneous Equations Worksheet — Level 2 — Practice Set 2 — Answers
Solve each pair of equations. Check your solution satisfies both equations.
1.Solve simultaneously: 3x + 4y = 18 and 3x − 3y = −3
Answer: x = 2, y = 3
- Subtract equation 2 from equation 1: 7y = 21
- y = 3
- Substitute into equation 1: 3x + 12 = 18, so x = 2
2.Solve simultaneously: 4x + 4y = 40 and 4x − 5y = −32
Answer: x = 2, y = 8
- Subtract equation 2 from equation 1: 9y = 72
- y = 8
- Substitute into equation 1: 4x + 32 = 40, so x = 2
3.Solve simultaneously: 4x + y = −30 and 4x − 2y = −12
Answer: x = −6, y = −6
- Subtract equation 2 from equation 1: 3y = −18
- y = −6
- Substitute into equation 1: 4x − 6 = −30, so x = −6
4.Solve simultaneously: 2x + 3y = 2 and 2x − 2y = −18
Answer: x = −5, y = 4
- Subtract equation 2 from equation 1: 5y = 20
- y = 4
- Substitute into equation 1: 2x + 12 = 2, so x = −5
5.Solve simultaneously: 4x + 2y = 6 and 4x − 3y = 11
Answer: x = 2, y = −1
- Subtract equation 2 from equation 1: 5y = −5
- y = −1
- Substitute into equation 1: 4x − 2 = 6, so x = 2
6.Solve simultaneously: 3x + y = 19 and 3x − 2y = 16
Answer: x = 6, y = 1
- Subtract equation 2 from equation 1: 3y = 3
- y = 1
- Substitute into equation 1: 3x + 1 = 19, so x = 6
7.Solve simultaneously: 3x + 4y = 40 and 3x − 2y = −2
Answer: x = 4, y = 7
- Subtract equation 2 from equation 1: 6y = 42
- y = 7
- Substitute into equation 1: 3x + 28 = 40, so x = 4
8.Solve simultaneously: 4x + y = −1 and 4x − 3y = 19
Answer: x = 1, y = −5
- Subtract equation 2 from equation 1: 4y = −20
- y = −5
- Substitute into equation 1: 4x − 5 = −1, so x = 1
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.
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