Year 12 Simultaneous Equations Worksheet — Level 2 — Practice Set 4 — Answers
Answer sheet with worked solutions for the Year 12 simultaneous equations worksheet.
Year 12 Simultaneous Equations Worksheet — Level 2 — Practice Set 4 — Answers
Solve each pair of equations. Check your solution satisfies both equations.
1.Solve simultaneously: 4x + 4y = 20 and 4x − 5y = −7
Answer: x = 2, y = 3
- Subtract equation 2 from equation 1: 9y = 27
- y = 3
- Substitute into equation 1: 4x + 12 = 20, so x = 2
2.Solve simultaneously: 4x + 2y = −4 and 4x − 3y = 26
Answer: x = 2, y = −6
- Subtract equation 2 from equation 1: 5y = −30
- y = −6
- Substitute into equation 1: 4x − 12 = −4, so x = 2
3.Solve simultaneously: 3x + 2y = −12 and 3x − 3y = −27
Answer: x = −6, y = 3
- Subtract equation 2 from equation 1: 5y = 15
- y = 3
- Substitute into equation 1: 3x + 6 = −12, so x = −6
4.Solve simultaneously: 2x + y = 1 and 2x − 3y = −27
Answer: x = −3, y = 7
- Subtract equation 2 from equation 1: 4y = 28
- y = 7
- Substitute into equation 1: 2x + 7 = 1, so x = −3
5.Solve simultaneously: 3x + 4y = 47 and 3x − 2y = −1
Answer: x = 5, y = 8
- Subtract equation 2 from equation 1: 6y = 48
- y = 8
- Substitute into equation 1: 3x + 32 = 47, so x = 5
6.Solve simultaneously: 3x + 4y = −30 and 3x − 5y = 24
Answer: x = −2, y = −6
- Subtract equation 2 from equation 1: 9y = −54
- y = −6
- Substitute into equation 1: 3x − 24 = −30, so x = −2
7.Solve simultaneously: 3x + y = −11 and 3x − 3y = −27
Answer: x = −5, y = 4
- Subtract equation 2 from equation 1: 4y = 16
- y = 4
- Substitute into equation 1: 3x + 4 = −11, so x = −5
8.Solve simultaneously: 2x + 4y = 6 and 2x − 5y = 15
Answer: x = 5, y = −1
- Subtract equation 2 from equation 1: 9y = −9
- y = −1
- Substitute into equation 1: 2x − 4 = 6, 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.
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