Year 10 Simultaneous Equations Worksheet — Level 3 — Practice Set 3 — Answers
Answer sheet with worked solutions for the Year 10 simultaneous equations worksheet.
Year 10 Simultaneous Equations Worksheet — Level 3 — Practice Set 3 — Answers
Solve each pair of equations. Check your solution satisfies both equations.
1.Solve simultaneously: 2x − 2y = −4 and 2x − y = 3
Answer: x = 5, y = 7
- Subtract equation 2 from equation 1: −y = −7
- y = 7
- Substitute into equation 1: 2x − 14 = −4, so x = 5
2.Solve simultaneously: 4x + 2y = 12 and 3x − 3y = −9
Answer: x = 1, y = 4
- Multiply equation 1 by 3 and equation 2 by 4 to match the x coefficients
- 12x + 6y = 36 and 12x − 12y = −36
- Subtract: 18y = 72, so y = 4
- Substitute back: x = 1
3.Solve simultaneously: 3x + 4y = 23 and 4x − 5y = −21
Answer: x = 1, y = 5
- Multiply equation 1 by 4 and equation 2 by 3 to match the x coefficients
- 12x + 16y = 92 and 12x − 15y = −63
- Subtract: 31y = 155, so y = 5
- Substitute back: x = 1
4.Solve simultaneously: 4x + y = −6 and 2x + 4y = 4
Answer: x = −2, y = 2
- Multiply equation 1 by 2 and equation 2 by 4 to match the x coefficients
- 8x + 2y = −12 and 8x + 16y = 16
- Subtract: −14y = −28, so y = 2
- Substitute back: x = −2
5.Solve simultaneously: 4x − 4y = 24 and 5x − 4y = 26
Answer: x = 2, y = −4
- Multiply equation 1 by 5 and equation 2 by 4 to match the x coefficients
- 20x − 20y = 120 and 20x − 16y = 104
- Subtract: −4y = 16, so y = −4
- Substitute back: x = 2
6.Solve simultaneously: 3x + 4y = 12 and 2x − y = −14
Answer: x = −4, y = 6
- Multiply equation 1 by 2 and equation 2 by 3 to match the x coefficients
- 6x + 8y = 24 and 6x − 3y = −42
- Subtract: 11y = 66, so y = 6
- Substitute back: x = −4
7.Solve simultaneously: 4x + 2y = 2 and 4x + 4y = 0
Answer: x = 1, y = −1
- Subtract equation 2 from equation 1: −2y = 2
- y = −1
- Substitute into equation 1: 4x − 2 = 2, so x = 1
8.Solve simultaneously: 4x + y = −15 and 5x − 4y = −24
Answer: x = −4, y = 1
- Multiply equation 1 by 5 and equation 2 by 4 to match the x coefficients
- 20x + 5y = −75 and 20x − 16y = −96
- Subtract: 21y = 21, so y = 1
- Substitute back: x = −4
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.