Explanation:
We are given two values:
- $ x = 8 $
- $ y = 4 $
We need to plug these numbers into each algebraic expression and simplify.
Let’s go one by one:
1. $ x + y = 8 + 4 = 12 $
2. $ 2 + x - y = 2 + 8 - 4 = 6 $
3. $ 12 + y - x = 12 + 4 - 8 = 8 $
4. $ x - 6 = 8 - 6 = 2 $
5. $ x + y - 6 = 8 + 4 - 6 = 6 $
6. $ 17 + x - y = 17 + 8 - 4 = 21 $
7. $ x + y + 3 = 8 + 4 + 3 = 15 $
8. $ x - 3 + 8 = 8 - 3 + 8 = 13 $
9. $ y - 2 + 4 = 4 - 2 + 4 = 6 $
10. $ x - y = 8 - 4 = 4 $
11. $ 8 - x + y = 8 - 8 + 4 = 4 $
12. $ 14 - y = 14 - 4 = 10 $
13. $ x - y + 6 = 8 - 4 + 6 = 10 $
14. $ y - 1 + x = 4 - 1 + 8 = 11 $
15. $ x - 2 - y = 8 - 2 - 4 = 2 $
16. $ y + 15 - 3 = 4 + 15 - 3 = 16 $
17. $ 12 - (x + y) = 12 - (8 + 4) = 12 - 12 = 0 $
18. $ x - y - 3 = 8 - 4 - 3 = 1 $
19. $ 11 - x + y = 11 - 8 + 4 = 7 $
20. $ x - y - 2 = 8 - 4 - 2 = 2 $
Double-check a few tricky ones:
- #17: parentheses first → $ x + y = 12 $, then $ 12 - 12 = 0 $
✔
- #14: left to right: $ y - 1 = 3 $, then $ 3 + x = 11 $
✔
- #19: $ 11 - 8 = 3 $, $ 3 + 4 = 7 $
✔
All calculations look correct.
Final Answer:
1. 12
2. 6
3. 8
4. 2
5. 6
6. 21
7. 15
8. 13
9. 6
10. 4
11. 4
12. 10
13. 10
14. 11
15. 2
16. 16
17. 0
18. 1
19. 7
20. 2
Parent Tip: Review the logic above to help your child master the concept of substituting variables worksheet.
