Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 529 · 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 a² − b² = (a + b)(a − b) to find 52² − 8².
2. 2.Use (a − b)² = a² − 2ab + b² to find 55².
3. 3.Use (a + b)(a − b) = a² − b² to find 61 × 59.
4. 4.Find the value of x² + 2xy + y² when x = 7 and y = 6.
5. 5.Use (a + b)² = a² + 2ab + b² to find 72².
6. 6.Use a² − b² = (a + b)(a − b) to find 21² − 20².
7. 7.Use (a − b)² = a² − 2ab + b² to find 79².
8. 8.Use (a − b)² = a² − 2ab + b² to find 89².
9. 9.Use (a + b)² = a² + 2ab + b² to find 35².
10. 10.If a + b = 12 and ab = 20, what is a² + b²?
11. 11.Use (a + b)(a − b) = a² − b² to find 82 × 78.
12. 12.Use (a − b)² = a² − 2ab + b² to find 34².
13. 13.Use (a − b)² = a² − 2ab + b² to find 76².
14. 14.Use (a − b)² = a² − 2ab + b² to find 27².
15. 15.Use (a + b)² = a² + 2ab + b² to find 13².
16. 16.Use (a + b)² = a² + 2ab + b² to find 73².
17. 17.Use (a + b)² = a² + 2ab + b² to find 22².
18. 18.Use (a + b)(a − b) = a² − b² to find 46 × 34.
19. 19.Use (a − b)² = a² − 2ab + b² to find 57².
20. 20.If a + b = 10 and ab = 9, what is a² + b²?
21. 21.If a + b = 5 and ab = 6, what is a² + b²?
22. 22.If a − b = 5 and ab = 6, what is a² + b²?
23. 23.Use (a − b)² = a² − 2ab + b² to find 63².
24. 24.Use (a + b)(a − b) = a² − b² to find 94 × 86.
25. 25.Use (a + b)² = a² + 2ab + b² to find 46².
26. 26.Use (a + b)(a − b) = a² − b² to find 22 × 18.
27. 27.Use (a + b)² = a² + 2ab + b² to find 86².
28. 28.Use a² − b² = (a + b)(a − b) to find 96² − 74².
29. 29.Find the value of x² + 2xy + y² when x = 3 and y = 1.
30. 30.Use (a + b)(a − b) = a² − b² to find 26 × 14.
31. 31.If a − b = 2 and ab = 3, what is a² + b²?
32. 32.Use (a + b)² = a² + 2ab + b² to find 91².
33. 33.Use (a − b)² = a² − 2ab + b² to find 26².
34. 34.Use a² − b² = (a + b)(a − b) to find 30² − 14².
35. 35.Use (a + b)² = a² + 2ab + b² to find 103².
36. 36.Find the value of x² + 2xy + y² when x = 12 and y = 3.
37. 37.Use (a − b)² = a² − 2ab + b² to find 96².
38. 38.Use (a + b)² = a² + 2ab + b² to find 81².
39. 39.Use (a + b)² = a² + 2ab + b² to find 68².
40. 40.Use (a − b)² = a² − 2ab + b² to find 85².

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