Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 743 · 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 65².
2. 2.Use (a − b)² = a² − 2ab + b² to find 35².
3. 3.If a + b = 5 and ab = 4, what is a² + b²?
4. 4.Use (a − b)² = a² − 2ab + b² to find 59².
5. 5.Use (a − b)² = a² − 2ab + b² to find 92².
6. 6.If a − b = 2 and ab = 120, what is a² + b²?
7. 7.If a + b = 7 and ab = 12, what is a² + b²?
8. 8.If a + b = 14 and ab = 24, what is a² + b²?
9. 9.Use (a + b)² = a² + 2ab + b² to find 95².
10. 10.Use a² − b² = (a + b)(a − b) to find 89² − 14².
11. 11.Use (a + b)² = a² + 2ab + b² to find 72².
12. 12.Use a² − b² = (a + b)(a − b) to find 97² − 30².
13. 13.Use (a + b)² = a² + 2ab + b² to find 64².
14. 14.Use (a − b)² = a² − 2ab + b² to find 17².
15. 15.Use a² − b² = (a + b)(a − b) to find 86² − 34².
16. 16.Use (a − b)² = a² − 2ab + b² to find 38².
17. 17.Use (a − b)² = a² − 2ab + b² to find 27².
18. 18.If a − b = 1 and ab = 20, what is a² + b²?
19. 19.Use a² − b² = (a + b)(a − b) to find 20² − 2².
20. 20.Use (a + b)(a − b) = a² − b² to find 96 × 84.
21. 21.Use (a + b)² = a² + 2ab + b² to find 54².
22. 22.Use (a − b)² = a² − 2ab + b² to find 18².
23. 23.Use (a + b)(a − b) = a² − b² to find 91 × 89.
24. 24.Use (a + b)(a − b) = a² − b² to find 38 × 22.
25. 25.If a + b = 8 and ab = 12, what is a² + b²?
26. 26.Use (a − b)² = a² − 2ab + b² to find 89².
27. 27.Use (a + b)(a − b) = a² − b² to find 98 × 82.
28. 28.Use (a + b)(a − b) = a² − b² to find 97 × 83.
29. 29.If a − b = 1 and ab = 6, what is a² + b²?
30. 30.Use (a + b)² = a² + 2ab + b² to find 84².
31. 31.Use (a + b)² = a² + 2ab + b² to find 32².
32. 32.Use (a + b)² = a² + 2ab + b² to find 28².
33. 33.Use (a − b)² = a² − 2ab + b² to find 25².
34. 34.Use (a + b)(a − b) = a² − b² to find 44 × 36.
35. 35.Find the value of x² − y² when x = 3 and y = 1.
36. 36.Use (a + b)² = a² + 2ab + b² to find 38².
37. 37.Use (a + b)² = a² + 2ab + b² to find 105².
38. 38.Use (a − b)² = a² − 2ab + b² to find 34².
39. 39.Use (a + b)(a − b) = a² − b² to find 93 × 87.
40. 40.Use (a + b)(a − b) = a² − b² to find 31 × 29.

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