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)(a − b) = a² − b² to find 33 × 27.
- 2.If a − b = 1 and ab = 2, what is a² + b²?
- 3.Use a² − b² = (a + b)(a − b) to find 27² − 1².
- 4.Use (a − b)² = a² − 2ab + b² to find 59².
- 5.Use (a + b)² = a² + 2ab + b² to find 32².
- 6.Use (a − b)² = a² − 2ab + b² to find 35².
- 7.Use (a − b)² = a² − 2ab + b² to find 39².
- 8.Find the value of x² − y² when x = 6 and y = 1.
- 9.Use (a + b)² = a² + 2ab + b² to find 59².
- 10.Use a² − b² = (a + b)(a − b) to find 28² − 14².
- 11.Find the value of x² − y² when x = 8 and y = 3.
- 12.Find the value of x² − 2xy + y² when x = 12 and y = 8.
- 13.Use (a + b)(a − b) = a² − b² to find 35 × 25.
- 14.Use (a − b)² = a² − 2ab + b² to find 54².
- 15.Use (a − b)² = a² − 2ab + b² to find 25².
- 16.Find the value of x² − y² when x = 15 and y = 3.
- 17.Use (a − b)² = a² − 2ab + b² to find 17².
- 18.Use (a + b)(a − b) = a² − b² to find 97 × 83.
- 19.If a − b = 2 and ab = 3, what is a² + b²?
- 20.Use a² − b² = (a + b)(a − b) to find 61² − 15².
- 21.Use (a + b)(a − b) = a² − b² to find 57 × 43.
- 22.Use (a − b)² = a² − 2ab + b² to find 49².
- 23.Use (a + b)(a − b) = a² − b² to find 58 × 42.
- 24.Use a² − b² = (a + b)(a − b) to find 56² − 4².
- 25.Use (a + b)² = a² + 2ab + b² to find 106².
- 26.Use (a − b)² = a² − 2ab + b² to find 64².
- 27.If a + b = 5 and ab = 4, what is a² + b²?
- 28.Use (a − b)² = a² − 2ab + b² to find 26².
- 29.If a − b = 3 and ab = 10, what is a² + b²?
- 30.If a + b = 11 and ab = 18, what is a² + b²?
- 31.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 32.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 33.Find the value of x² + 2xy + y² when x = 13 and y = 7.
- 34.Find the value of x² + 2xy + y² when x = 9 and y = 3.
- 35.Find the value of x² − y² when x = 6 and y = 3.
- 36.Use (a + b)(a − b) = a² − b² to find 51 × 49.
- 37.Use (a + b)(a − b) = a² − b² to find 27 × 13.
- 38.Use (a + b)² = a² + 2ab + b² to find 51².
- 39.Use (a + b)² = a² + 2ab + b² to find 61².
- 40.Use (a − b)² = a² − 2ab + b² to find 55².
Answer key
- 891
- 5
- 728
- 3481
- 1024
- 1225
- 1521
- 35
- 3481
- 588
- 55
- 16
- 875
- 2916
- 625
- 216
- 289
- 8051
- 10
- 3496
- 2451
- 2401
- 2436
- 3120
- 11236
- 4096
- 17
- 676
- 29
- 85
- 1536
- 1599
- 400
- 144
- 27
- 2499
- 351
- 2601
- 3721
- 3025
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