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 a² − b² = (a + b)(a − b) to find 55² − 32².
- 2.Use a² − b² = (a + b)(a − b) to find 37² − 30².
- 3.Use (a + b)(a − b) = a² − b² to find 96 × 84.
- 4.Use (a + b)(a − b) = a² − b² to find 67 × 53.
- 5.Use (a − b)² = a² − 2ab + b² to find 78².
- 6.Use a² − b² = (a + b)(a − b) to find 62² − 2².
- 7.Use (a + b)² = a² + 2ab + b² to find 36².
- 8.Use (a − b)² = a² − 2ab + b² to find 89².
- 9.If a + b = 18 and ab = 77, what is a² + b²?
- 10.If a − b = 1 and ab = 6, what is a² + b²?
- 11.Use (a + b)² = a² + 2ab + b² to find 85².
- 12.Use (a − b)² = a² − 2ab + b² to find 45².
- 13.Use (a + b)² = a² + 2ab + b² to find 91².
- 14.Use (a − b)² = a² − 2ab + b² to find 46².
- 15.Find the value of x² − y² when x = 4 and y = 3.
- 16.Use a² − b² = (a + b)(a − b) to find 36² − 22².
- 17.Use (a + b)(a − b) = a² − b² to find 23 × 17.
- 18.Use a² − b² = (a + b)(a − b) to find 90² − 46².
- 19.Use a² − b² = (a + b)(a − b) to find 91² − 36².
- 20.Use a² − b² = (a + b)(a − b) to find 38² − 29².
- 21.Use (a + b)(a − b) = a² − b² to find 32 × 28.
- 22.Use (a + b)² = a² + 2ab + b² to find 86².
- 23.Find the value of x² − y² when x = 12 and y = 3.
- 24.Use (a − b)² = a² − 2ab + b² to find 54².
- 25.Use (a − b)² = a² − 2ab + b² to find 76².
- 26.Use (a − b)² = a² − 2ab + b² to find 37².
- 27.If a − b = 6 and ab = 16, what is a² + b²?
- 28.Find the value of x² − y² when x = 10 and y = 8.
- 29.Find the value of x² − y² when x = 11 and y = 9.
- 30.Find the value of x² − 2xy + y² when x = 5 and y = 3.
- 31.Use (a − b)² = a² − 2ab + b² to find 52².
- 32.Use a² − b² = (a + b)(a − b) to find 27² − 17².
- 33.If a − b = 2 and ab = 80, what is a² + b²?
- 34.Use (a − b)² = a² − 2ab + b² to find 44².
- 35.Find the value of x² − y² when x = 7 and y = 6.
- 36.Find the value of x² + 2xy + y² when x = 5 and y = 3.
- 37.Use a² − b² = (a + b)(a − b) to find 28² − 2².
- 38.Use (a − b)² = a² − 2ab + b² to find 87².
- 39.If a + b = 11 and ab = 28, what is a² + b²?
- 40.Use (a + b)(a − b) = a² − b² to find 31 × 29.
Answer key
- 2001
- 469
- 8064
- 3551
- 6084
- 3840
- 1296
- 7921
- 170
- 13
- 7225
- 2025
- 8281
- 2116
- 7
- 812
- 391
- 5984
- 6985
- 603
- 896
- 7396
- 135
- 2916
- 5776
- 1369
- 68
- 36
- 40
- 4
- 2704
- 440
- 164
- 1936
- 13
- 64
- 780
- 7569
- 65
- 899
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