Class 8 Maths Worksheet: Algebraic Identities
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.
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- 1.Use (a + b)² = a² + 2ab + b² to find 86².
- 2.Use (a − b)² = a² − 2ab + b² to find 37².
- 3.Use a² − b² = (a + b)(a − b) to find 39² − 34².
- 4.Use (a + b)² = a² + 2ab + b² to find 23².
- 5.Use (a − b)² = a² − 2ab + b² to find 61².
- 6.Use (a + b)(a − b) = a² − b² to find 103 × 97.
- 7.Use (a + b)(a − b) = a² − b² to find 26 × 14.
- 8.Use a² − b² = (a + b)(a − b) to find 32² − 3².
- 9.Use (a + b)² = a² + 2ab + b² to find 55².
- 10.Use a² − b² = (a + b)(a − b) to find 67² − 39².
- 11.Find the value of x² − y² when x = 7 and y = 4.
- 12.Use a² − b² = (a + b)(a − b) to find 88² − 49².
- 13.Use a² − b² = (a + b)(a − b) to find 23² − 21².
- 14.Find the value of x² + 2xy + y² when x = 3 and y = 2.
- 15.Use (a + b)(a − b) = a² − b² to find 28 × 12.
- 16.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 17.Use a² − b² = (a + b)(a − b) to find 24² − 6².
- 18.Use (a + b)(a − b) = a² − b² to find 23 × 17.
- 19.Use a² − b² = (a + b)(a − b) to find 21² − 16².
- 20.Use (a + b)(a − b) = a² − b² to find 39 × 21.
- 21.Use (a − b)² = a² − 2ab + b² to find 66².
- 22.Use (a + b)(a − b) = a² − b² to find 65 × 55.
- 23.Use a² − b² = (a + b)(a − b) to find 95² − 94².
- 24.Find the value of x² + 2xy + y² when x = 4 and y = 3.
- 25.Use (a + b)² = a² + 2ab + b² to find 24².
- 26.Find the value of x² − 2xy + y² when x = 12 and y = 2.
- 27.Use (a + b)² = a² + 2ab + b² to find 22².
- 28.If a − b = 3 and ab = 10, what is a² + b²?
- 29.Find the value of x² − 2xy + y² when x = 12 and y = 1.
- 30.Use (a + b)(a − b) = a² − b² to find 89 × 71.
- 31.If a − b = 8 and ab = 33, what is a² + b²?
- 32.Use (a + b)(a − b) = a² − b² to find 105 × 95.
- 33.Use a² − b² = (a + b)(a − b) to find 93² − 60².
- 34.Use a² − b² = (a + b)(a − b) to find 98² − 79².
- 35.Use (a − b)² = a² − 2ab + b² to find 46².
- 36.Use a² − b² = (a + b)(a − b) to find 31² − 2².
- 37.If a + b = 3 and ab = 2, what is a² + b²?
- 38.Use a² − b² = (a + b)(a − b) to find 61² − 4².
- 39.Use (a + b)² = a² + 2ab + b² to find 17².
- 40.If a + b = 6 and ab = 5, what is a² + b²?
Answer key
- 7396
- 1369
- 365
- 529
- 3721
- 9991
- 364
- 1015
- 3025
- 2968
- 33
- 5343
- 88
- 25
- 336
- 1599
- 540
- 391
- 185
- 819
- 4356
- 3575
- 189
- 49
- 576
- 100
- 484
- 29
- 121
- 6319
- 130
- 9975
- 5049
- 3363
- 2116
- 957
- 5
- 3705
- 289
- 26
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