Class 8 Maths Worksheet: Algebraic Identities

Maths worksheets lesson 61: Algebraic identities · Set 70 · 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 86² − 78².
2. 2.Use a² − b² = (a + b)(a − b) to find 63² − 23².
3. 3.Use (a − b)² = a² − 2ab + b² to find 73².
4. 4.If a − b = 5 and ab = 6, what is a² + b²?
5. 5.Use (a + b)² = a² + 2ab + b² to find 58².
6. 6.Use (a − b)² = a² − 2ab + b² to find 19².
7. 7.If a − b = 4 and ab = 5, what is a² + b²?
8. 8.Use (a + b)² = a² + 2ab + b² to find 105².
9. 9.Find the value of x² + 2xy + y² when x = 3 and y = 1.
10. 10.If a + b = 14 and ab = 24, what is a² + b²?
11. 11.Find the value of x² + 2xy + y² when x = 14 and y = 11.
12. 12.Find the value of x² − y² when x = 12 and y = 2.
13. 13.Find the value of x² − y² when x = 14 and y = 7.
14. 14.If a + b = 5 and ab = 6, what is a² + b²?
15. 15.Use (a + b)(a − b) = a² − b² to find 35 × 25.
16. 16.Find the value of x² − 2xy + y² when x = 3 and y = 2.
17. 17.Use a² − b² = (a + b)(a − b) to find 91² − 23².
18. 18.Use (a − b)² = a² − 2ab + b² to find 91².
19. 19.Use (a + b)² = a² + 2ab + b² to find 31².
20. 20.Use (a − b)² = a² − 2ab + b² to find 68².
21. 21.Use (a + b)² = a² + 2ab + b² to find 71².
22. 22.Use (a + b)(a − b) = a² − b² to find 78 × 62.
23. 23.Use (a + b)(a − b) = a² − b² to find 102 × 98.
24. 24.Use (a + b)² = a² + 2ab + b² to find 34².
25. 25.If a − b = 1 and ab = 6, what is a² + b²?
26. 26.If a − b = 2 and ab = 63, what is a² + b²?
27. 27.Use a² − b² = (a + b)(a − b) to find 62² − 12².
28. 28.Use (a + b)² = a² + 2ab + b² to find 79².
29. 29.Use (a − b)² = a² − 2ab + b² to find 25².
30. 30.Use a² − b² = (a + b)(a − b) to find 20² − 1².
31. 31.Find the value of x² − 2xy + y² when x = 11 and y = 8.
32. 32.Use a² − b² = (a + b)(a − b) to find 34² − 12².
33. 33.Find the value of x² − 2xy + y² when x = 7 and y = 6.
34. 34.If a + b = 11 and ab = 10, what is a² + b²?
35. 35.Use (a + b)² = a² + 2ab + b² to find 57².
36. 36.Find the value of x² + 2xy + y² when x = 8 and y = 4.
37. 37.Use (a + b)(a − b) = a² − b² to find 89 × 71.
38. 38.If a + b = 12 and ab = 27, what is a² + b²?
39. 39.Use (a + b)² = a² + 2ab + b² to find 49².
40. 40.Use (a − b)² = a² − 2ab + b² to find 21².

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