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 52 × 48.
- 2.If a − b = 5 and ab = 84, what is a² + b²?
- 3.Use a² − b² = (a + b)(a − b) to find 66² − 44².
- 4.Use a² − b² = (a + b)(a − b) to find 89² − 30².
- 5.Find the value of x² + 2xy + y² when x = 13 and y = 9.
- 6.Use (a + b)² = a² + 2ab + b² to find 49².
- 7.Use (a + b)(a − b) = a² − b² to find 32 × 28.
- 8.Use a² − b² = (a + b)(a − b) to find 62² − 25².
- 9.Use (a + b)(a − b) = a² − b² to find 57 × 43.
- 10.Use (a + b)² = a² + 2ab + b² to find 45².
- 11.Use (a − b)² = a² − 2ab + b² to find 26².
- 12.If a + b = 11 and ab = 30, what is a² + b²?
- 13.Find the value of x² − 2xy + y² when x = 10 and y = 2.
- 14.If a − b = 3 and ab = 108, what is a² + b²?
- 15.Use a² − b² = (a + b)(a − b) to find 67² − 16².
- 16.Use (a − b)² = a² − 2ab + b² to find 74².
- 17.Use (a + b)(a − b) = a² − b² to find 86 × 74.
- 18.Find the value of x² − y² when x = 3 and y = 2.
- 19.Use a² − b² = (a + b)(a − b) to find 50² − 15².
- 20.Use (a − b)² = a² − 2ab + b² to find 37².
- 21.Use (a + b)² = a² + 2ab + b² to find 97².
- 22.Find the value of x² − y² when x = 12 and y = 9.
- 23.Use (a + b)² = a² + 2ab + b² to find 46².
- 24.Use (a − b)² = a² − 2ab + b² to find 24².
- 25.Use (a + b)² = a² + 2ab + b² to find 93².
- 26.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 27.Find the value of x² − y² when x = 8 and y = 1.
- 28.Use a² − b² = (a + b)(a − b) to find 24² − 12².
- 29.Use (a + b)² = a² + 2ab + b² to find 65².
- 30.Use (a + b)² = a² + 2ab + b² to find 68².
- 31.Use a² − b² = (a + b)(a − b) to find 48² − 35².
- 32.Use (a − b)² = a² − 2ab + b² to find 21².
- 33.If a + b = 7 and ab = 12, what is a² + b²?
- 34.Use (a + b)(a − b) = a² − b² to find 37 × 23.
- 35.Use (a + b)(a − b) = a² − b² to find 58 × 42.
- 36.If a + b = 10 and ab = 24, what is a² + b²?
- 37.If a + b = 13 and ab = 36, what is a² + b²?
- 38.Use (a + b)² = a² + 2ab + b² to find 59².
- 39.Use (a − b)² = a² − 2ab + b² to find 11².
- 40.If a + b = 5 and ab = 4, what is a² + b²?
Answer key
- 2496
- 193
- 2420
- 7021
- 484
- 2401
- 896
- 3219
- 2451
- 2025
- 676
- 61
- 64
- 225
- 4233
- 5476
- 6364
- 5
- 2275
- 1369
- 9409
- 63
- 2116
- 576
- 8649
- 1536
- 63
- 432
- 4225
- 4624
- 1079
- 441
- 25
- 851
- 2436
- 52
- 97
- 3481
- 121
- 17
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