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 66².
- 2.Use (a + b)(a − b) = a² − b² to find 27 × 13.
- 3.Use (a + b)² = a² + 2ab + b² to find 64².
- 4.Use (a − b)² = a² − 2ab + b² to find 67².
- 5.Use (a + b)² = a² + 2ab + b² to find 11².
- 6.If a + b = 10 and ab = 9, what is a² + b²?
- 7.Use (a + b)² = a² + 2ab + b² to find 73².
- 8.Use (a + b)(a − b) = a² − b² to find 72 × 68.
- 9.Use a² − b² = (a + b)(a − b) to find 87² − 54².
- 10.Use (a − b)² = a² − 2ab + b² to find 83².
- 11.Use a² − b² = (a + b)(a − b) to find 64² − 63².
- 12.Use (a − b)² = a² − 2ab + b² to find 37².
- 13.Use (a + b)² = a² + 2ab + b² to find 89².
- 14.Use (a − b)² = a² − 2ab + b² to find 38².
- 15.If a + b = 11 and ab = 30, 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 97².
- 18.If a + b = 11 and ab = 10, what is a² + b²?
- 19.Use (a − b)² = a² − 2ab + b² to find 98².
- 20.Use a² − b² = (a + b)(a − b) to find 38² − 9².
- 21.Use a² − b² = (a + b)(a − b) to find 63² − 39².
- 22.Find the value of x² + 2xy + y² when x = 12 and y = 9.
- 23.Use (a − b)² = a² − 2ab + b² to find 34².
- 24.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 25.Use (a − b)² = a² − 2ab + b² to find 57².
- 26.Find the value of x² − 2xy + y² when x = 12 and y = 10.
- 27.Use (a + b)² = a² + 2ab + b² to find 32².
- 28.Use (a + b)² = a² + 2ab + b² to find 26².
- 29.Use (a + b)² = a² + 2ab + b² to find 24².
- 30.Use (a − b)² = a² − 2ab + b² to find 17².
- 31.Use a² − b² = (a + b)(a − b) to find 39² − 6².
- 32.Use a² − b² = (a + b)(a − b) to find 75² − 74².
- 33.Use (a + b)² = a² + 2ab + b² to find 74².
- 34.Use (a + b)(a − b) = a² − b² to find 58 × 42.
- 35.Use (a − b)² = a² − 2ab + b² to find 55².
- 36.Find the value of x² − 2xy + y² when x = 15 and y = 1.
- 37.Use a² − b² = (a + b)(a − b) to find 80² − 1².
- 38.Use (a + b)² = a² + 2ab + b² to find 49².
- 39.Use (a + b)(a − b) = a² − b² to find 105 × 95.
- 40.Find the value of x² − 2xy + y² when x = 3 and y = 1.
Answer key
- 4356
- 351
- 4096
- 4489
- 121
- 82
- 5329
- 4896
- 4653
- 6889
- 127
- 1369
- 7921
- 1444
- 61
- 117
- 9409
- 101
- 9604
- 1363
- 2448
- 441
- 1156
- 1536
- 3249
- 4
- 1024
- 676
- 576
- 289
- 1485
- 149
- 5476
- 2436
- 3025
- 196
- 6399
- 2401
- 9975
- 4
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