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 33².
- 2.Find the value of x² + 2xy + y² when x = 3 and y = 1.
- 3.If a + b = 8 and ab = 7, what is a² + b²?
- 4.Find the value of x² − 2xy + y² when x = 3 and y = 2.
- 5.Use a² − b² = (a + b)(a − b) to find 66² − 48².
- 6.Use (a + b)(a − b) = a² − b² to find 33 × 27.
- 7.Use (a − b)² = a² − 2ab + b² to find 51².
- 8.Use (a + b)² = a² + 2ab + b² to find 41².
- 9.Use (a + b)(a − b) = a² − b² to find 101 × 99.
- 10.If a + b = 17 and ab = 66, what is a² + b²?
- 11.Use a² − b² = (a + b)(a − b) to find 88² − 22².
- 12.Use (a + b)(a − b) = a² − b² to find 39 × 21.
- 13.Use (a + b)(a − b) = a² − b² to find 83 × 77.
- 14.Use a² − b² = (a + b)(a − b) to find 45² − 42².
- 15.Use a² − b² = (a + b)(a − b) to find 52² − 24².
- 16.If a + b = 21 and ab = 110, what is a² + b²?
- 17.If a − b = 5 and ab = 66, what is a² + b²?
- 18.Use (a − b)² = a² − 2ab + b² to find 65².
- 19.Use (a + b)² = a² + 2ab + b² to find 19².
- 20.If a − b = 2 and ab = 8, what is a² + b²?
- 21.Use (a + b)² = a² + 2ab + b² to find 29².
- 22.If a − b = 2 and ab = 24, what is a² + b²?
- 23.Use a² − b² = (a + b)(a − b) to find 24² − 1².
- 24.Use (a + b)(a − b) = a² − b² to find 78 × 62.
- 25.Use (a + b)(a − b) = a² − b² to find 44 × 36.
- 26.Use (a + b)(a − b) = a² − b² to find 25 × 15.
- 27.Use (a + b)(a − b) = a² − b² to find 87 × 73.
- 28.If a + b = 9 and ab = 14, what is a² + b²?
- 29.Use a² − b² = (a + b)(a − b) to find 59² − 38².
- 30.Find the value of x² + 2xy + y² when x = 7 and y = 2.
- 31.Use (a − b)² = a² − 2ab + b² to find 98².
- 32.Use (a − b)² = a² − 2ab + b² to find 52².
- 33.Use a² − b² = (a + b)(a − b) to find 63² − 54².
- 34.Use a² − b² = (a + b)(a − b) to find 63² − 19².
- 35.Use a² − b² = (a + b)(a − b) to find 92² − 26².
- 36.Use (a + b)² = a² + 2ab + b² to find 69².
- 37.Use a² − b² = (a + b)(a − b) to find 34² − 26².
- 38.Use (a − b)² = a² − 2ab + b² to find 25².
- 39.If a − b = 1 and ab = 12, what is a² + b²?
- 40.Use (a − b)² = a² − 2ab + b² to find 18².
Answer key
- 1089
- 16
- 50
- 1
- 2052
- 891
- 2601
- 1681
- 9999
- 157
- 7260
- 819
- 6391
- 261
- 2128
- 221
- 157
- 4225
- 361
- 20
- 841
- 52
- 575
- 4836
- 1584
- 375
- 6351
- 53
- 2037
- 81
- 9604
- 2704
- 1053
- 3608
- 7788
- 4761
- 480
- 625
- 25
- 324
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