Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 880 · 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)(a − b) = a² − b² to find 82 × 78.
2. 2.Use (a + b)(a − b) = a² − b² to find 72 × 68.
3. 3.Use (a − b)² = a² − 2ab + b² to find 76².
4. 4.Find the value of x² − 2xy + y² when x = 13 and y = 11.
5. 5.Use (a + b)² = a² + 2ab + b² to find 18².
6. 6.Use (a + b)(a − b) = a² − b² to find 83 × 77.
7. 7.Find the value of x² + 2xy + y² when x = 5 and y = 2.
8. 8.Use (a + b)² = a² + 2ab + b² to find 13².
9. 9.Use (a − b)² = a² − 2ab + b² to find 81².
10. 10.Use a² − b² = (a + b)(a − b) to find 76² − 10².
11. 11.If a + b = 15 and ab = 50, what is a² + b²?
12. 12.Find the value of x² + 2xy + y² when x = 9 and y = 6.
13. 13.If a − b = 3 and ab = 10, what is a² + b²?
14. 14.Use (a + b)² = a² + 2ab + b² to find 67².
15. 15.Use a² − b² = (a + b)(a − b) to find 89² − 86².
16. 16.Use a² − b² = (a + b)(a − b) to find 67² − 21².
17. 17.Use (a + b)² = a² + 2ab + b² to find 31².
18. 18.Use a² − b² = (a + b)(a − b) to find 57² − 24².
19. 19.Use (a − b)² = a² − 2ab + b² to find 58².
20. 20.Use (a − b)² = a² − 2ab + b² to find 59².
21. 21.Find the value of x² − 2xy + y² when x = 12 and y = 2.
22. 22.If a − b = 4 and ab = 12, what is a² + b²?
23. 23.Use (a + b)(a − b) = a² − b² to find 63 × 57.
24. 24.If a + b = 10 and ab = 16, what is a² + b²?
25. 25.If a + b = 8 and ab = 15, what is a² + b²?
26. 26.Find the value of x² + 2xy + y² when x = 7 and y = 3.
27. 27.If a + b = 12 and ab = 32, what is a² + b²?
28. 28.Use (a − b)² = a² − 2ab + b² to find 33².
29. 29.Use a² − b² = (a + b)(a − b) to find 27² − 22².
30. 30.If a + b = 13 and ab = 36, what is a² + b²?
31. 31.Use a² − b² = (a + b)(a − b) to find 30² − 29².
32. 32.Use (a + b)² = a² + 2ab + b² to find 32².
33. 33.Use (a + b)² = a² + 2ab + b² to find 95².
34. 34.Find the value of x² − 2xy + y² when x = 12 and y = 4.
35. 35.Find the value of x² − y² when x = 10 and y = 1.
36. 36.If a + b = 14 and ab = 24, what is a² + b²?
37. 37.Find the value of x² + 2xy + y² when x = 11 and y = 10.
38. 38.Use (a + b)² = a² + 2ab + b² to find 12².
39. 39.Use a² − b² = (a + b)(a − b) to find 88² − 23².
40. 40.Use a² − b² = (a + b)(a − b) to find 74² − 1².

Free maths worksheets lessons, practice and worksheets at talentjr.in/maths-worksheets