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 63².
- 2.Use (a + b)(a − b) = a² − b² to find 45 × 35.
- 3.Find the value of x² − 2xy + y² when x = 4 and y = 3.
- 4.Use (a + b)² = a² + 2ab + b² to find 28².
- 5.Use a² − b² = (a + b)(a − b) to find 20² − 6².
- 6.Find the value of x² − 2xy + y² when x = 10 and y = 3.
- 7.Find the value of x² + 2xy + y² when x = 10 and y = 3.
- 8.Use a² − b² = (a + b)(a − b) to find 61² − 55².
- 9.Use a² − b² = (a + b)(a − b) to find 20² − 15².
- 10.Use a² − b² = (a + b)(a − b) to find 81² − 72².
- 11.Use (a − b)² = a² − 2ab + b² to find 44².
- 12.Use (a + b)² = a² + 2ab + b² to find 106².
- 13.Use (a + b)² = a² + 2ab + b² to find 87².
- 14.Use a² − b² = (a + b)(a − b) to find 75² − 64².
- 15.If a + b = 7 and ab = 6, what is a² + b²?
- 16.If a + b = 15 and ab = 54, what is a² + b²?
- 17.Use (a + b)² = a² + 2ab + b² to find 26².
- 18.Use (a + b)² = a² + 2ab + b² to find 65².
- 19.Use (a + b)(a − b) = a² − b² to find 33 × 27.
- 20.Use (a − b)² = a² − 2ab + b² to find 45².
- 21.Find the value of x² − 2xy + y² when x = 14 and y = 9.
- 22.Use (a − b)² = a² − 2ab + b² to find 96².
- 23.Use (a − b)² = a² − 2ab + b² to find 97².
- 24.If a + b = 3 and ab = 2, what is a² + b²?
- 25.Use (a + b)(a − b) = a² − b² to find 84 × 76.
- 26.Use a² − b² = (a + b)(a − b) to find 97² − 32².
- 27.Use (a + b)² = a² + 2ab + b² to find 84².
- 28.Use (a + b)(a − b) = a² − b² to find 101 × 99.
- 29.Use (a − b)² = a² − 2ab + b² to find 23².
- 30.Use (a + b)² = a² + 2ab + b² to find 22².
- 31.Use (a − b)² = a² − 2ab + b² to find 72².
- 32.If a + b = 13 and ab = 12, what is a² + b²?
- 33.Find the value of x² + 2xy + y² when x = 8 and y = 2.
- 34.Use (a + b)(a − b) = a² − b² to find 36 × 24.
- 35.Use (a − b)² = a² − 2ab + b² to find 73².
- 36.Use a² − b² = (a + b)(a − b) to find 60² − 46².
- 37.Use (a + b)² = a² + 2ab + b² to find 64².
- 38.Use (a − b)² = a² − 2ab + b² to find 52².
- 39.Use (a − b)² = a² − 2ab + b² to find 35².
- 40.Use (a + b)(a − b) = a² − b² to find 32 × 28.
Answer key
- 3969
- 1575
- 1
- 784
- 364
- 49
- 169
- 696
- 175
- 1377
- 1936
- 11236
- 7569
- 1529
- 37
- 117
- 676
- 4225
- 891
- 2025
- 25
- 9216
- 9409
- 5
- 6384
- 8385
- 7056
- 9999
- 529
- 484
- 5184
- 145
- 100
- 864
- 5329
- 1484
- 4096
- 2704
- 1225
- 896
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