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.
NameDateTime takenScore ___ / 40
- 1.Use (a + b)(a − b) = a² − b² to find 56 × 44.
- 2.Find the value of x² + 2xy + y² when x = 13 and y = 2.
- 3.Use (a + b)(a − b) = a² − b² to find 52 × 48.
- 4.If a − b = 1 and ab = 2, what is a² + b²?
- 5.Use (a + b)(a − b) = a² − b² to find 49 × 31.
- 6.Use a² − b² = (a + b)(a − b) to find 43² − 8².
- 7.Use (a + b)(a − b) = a² − b² to find 53 × 47.
- 8.Use (a − b)² = a² − 2ab + b² to find 18².
- 9.Use (a + b)² = a² + 2ab + b² to find 15².
- 10.Use (a + b)² = a² + 2ab + b² to find 67².
- 11.Use a² − b² = (a + b)(a − b) to find 98² − 18².
- 12.Use a² − b² = (a + b)(a − b) to find 47² − 32².
- 13.Find the value of x² − 2xy + y² when x = 3 and y = 1.
- 14.If a − b = 2 and ab = 35, what is a² + b²?
- 15.Use (a + b)² = a² + 2ab + b² to find 89².
- 16.Use a² − b² = (a + b)(a − b) to find 84² − 45².
- 17.Use (a + b)(a − b) = a² − b² to find 25 × 15.
- 18.Use a² − b² = (a + b)(a − b) to find 81² − 17².
- 19.Use (a + b)² = a² + 2ab + b² to find 52².
- 20.Use (a + b)² = a² + 2ab + b² to find 26².
- 21.Use (a − b)² = a² − 2ab + b² to find 38².
- 22.If a − b = 2 and ab = 24, what is a² + b²?
- 23.Use a² − b² = (a + b)(a − b) to find 77² − 39².
- 24.Use (a + b)² = a² + 2ab + b² to find 35².
- 25.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 26.If a + b = 8 and ab = 7, what is a² + b²?
- 27.Use (a + b)² = a² + 2ab + b² to find 93².
- 28.Use (a − b)² = a² − 2ab + b² to find 72².
- 29.Use (a + b)(a − b) = a² − b² to find 28 × 12.
- 30.If a + b = 12 and ab = 20, what is a² + b²?
- 31.Use (a + b)² = a² + 2ab + b² to find 14².
- 32.If a − b = 1 and ab = 6, what is a² + b²?
- 33.Use a² − b² = (a + b)(a − b) to find 52² − 45².
- 34.Use (a + b)² = a² + 2ab + b² to find 85².
- 35.Use (a + b)² = a² + 2ab + b² to find 66².
- 36.Find the value of x² − 2xy + y² when x = 8 and y = 7.
- 37.Find the value of x² − 2xy + y² when x = 11 and y = 10.
- 38.Find the value of x² + 2xy + y² when x = 5 and y = 3.
- 39.Find the value of x² − y² when x = 3 and y = 1.
- 40.Use (a − b)² = a² − 2ab + b² to find 17².
Answer key
- 2464
- 225
- 2496
- 5
- 1519
- 1785
- 2491
- 324
- 225
- 4489
- 9280
- 1185
- 4
- 74
- 7921
- 5031
- 375
- 6272
- 2704
- 676
- 1444
- 52
- 4408
- 1225
- 1599
- 50
- 8649
- 5184
- 336
- 104
- 196
- 13
- 679
- 7225
- 4356
- 1
- 1
- 64
- 8
- 289
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