Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 408 · 40 sums

The method (Split into easy parts): (a + b)² = a² + 2ab + b². (a − b)² = a² − 2ab + b². (a + b)(a − b) = a² − b²; so a² − b² = (a + b)(a − b). a² + b² = (a + b)² − 2ab = (a − b)² + 2ab.

1. 1.Use (a + b)² = a² + 2ab + b² to find 33².
2. 2.Use (a + b)(a − b) = a² − b² to find 96 × 84.
3. 3.Find the value of x² − y² when x = 14 and y = 1.
4. 4.Use (a − b)² = a² − 2ab + b² to find 21².
5. 5.Use (a + b)² = a² + 2ab + b² to find 46².
6. 6.Use a² − b² = (a + b)(a − b) to find 79² − 28².
7. 7.Use (a − b)² = a² − 2ab + b² to find 44².
8. 8.Use (a + b)² = a² + 2ab + b² to find 73².
9. 9.Use (a + b)² = a² + 2ab + b² to find 49².
10. 10.Use a² − b² = (a + b)(a − b) to find 39² − 37².
11. 11.Use (a + b)² = a² + 2ab + b² to find 38².
12. 12.Use (a − b)² = a² − 2ab + b² to find 94².
13. 13.Use (a + b)² = a² + 2ab + b² to find 59².
14. 14.If a − b = 2 and ab = 3, what is a² + b²?
15. 15.Use a² − b² = (a + b)(a − b) to find 59² − 45².
16. 16.Use a² − b² = (a + b)(a − b) to find 42² − 24².
17. 17.Use (a + b)² = a² + 2ab + b² to find 98².
18. 18.Use (a + b)(a − b) = a² − b² to find 77 × 63.
19. 19.If a − b = 4 and ab = 32, what is a² + b²?
20. 20.Use (a + b)² = a² + 2ab + b² to find 28².
21. 21.Use (a + b)² = a² + 2ab + b² to find 68².
22. 22.Use (a − b)² = a² − 2ab + b² to find 13².
23. 23.Use (a + b)(a − b) = a² − b² to find 99 × 81.
24. 24.Find the value of x² + 2xy + y² when x = 9 and y = 8.
25. 25.Use (a − b)² = a² − 2ab + b² to find 49².
26. 26.If a − b = 1 and ab = 72, what is a² + b²?
27. 27.Use (a − b)² = a² − 2ab + b² to find 43².
28. 28.Use (a − b)² = a² − 2ab + b² to find 16².
29. 29.Find the value of x² + 2xy + y² when x = 10 and y = 1.
30. 30.Use (a + b)(a − b) = a² − b² to find 41 × 39.
31. 31.If a − b = 1 and ab = 6, what is a² + b²?
32. 32.Use a² − b² = (a + b)(a − b) to find 73² − 28².
33. 33.Use (a + b)² = a² + 2ab + b² to find 31².
34. 34.Use (a + b)² = a² + 2ab + b² to find 48².
35. 35.Use (a + b)² = a² + 2ab + b² to find 44².
36. 36.Use (a + b)² = a² + 2ab + b² to find 13².
37. 37.Use (a + b)² = a² + 2ab + b² to find 34².
38. 38.If a + b = 5 and ab = 4, what is a² + b²?
39. 39.Find the value of x² − y² when x = 13 and y = 4.
40. 40.Use (a + b)(a − b) = a² − b² to find 27 × 13.

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