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 41² − 7².
- 2.Use (a + b)² = a² + 2ab + b² to find 47².
- 3.Find the value of x² − y² when x = 11 and y = 1.
- 4.Find the value of x² − 2xy + y² when x = 13 and y = 7.
- 5.Use (a − b)² = a² − 2ab + b² to find 68².
- 6.Use a² − b² = (a + b)(a − b) to find 20² − 15².
- 7.Find the value of x² − y² when x = 4 and y = 3.
- 8.Use a² − b² = (a + b)(a − b) to find 32² − 24².
- 9.Use (a + b)² = a² + 2ab + b² to find 95².
- 10.Use (a + b)(a − b) = a² − b² to find 64 × 56.
- 11.Find the value of x² + 2xy + y² when x = 12 and y = 2.
- 12.Use (a + b)² = a² + 2ab + b² to find 63².
- 13.If a − b = 5 and ab = 24, what is a² + b²?
- 14.Use (a + b)² = a² + 2ab + b² to find 42².
- 15.Use (a − b)² = a² − 2ab + b² to find 74².
- 16.Find the value of x² − 2xy + y² when x = 12 and y = 6.
- 17.Use (a + b)(a − b) = a² − b² to find 23 × 17.
- 18.Find the value of x² − y² when x = 8 and y = 1.
- 19.Use (a − b)² = a² − 2ab + b² to find 16².
- 20.Find the value of x² − y² when x = 10 and y = 6.
- 21.Find the value of x² + 2xy + y² when x = 3 and y = 2.
- 22.Use a² − b² = (a + b)(a − b) to find 38² − 29².
- 23.Use (a + b)(a − b) = a² − b² to find 25 × 15.
- 24.Use (a − b)² = a² − 2ab + b² to find 53².
- 25.Find the value of x² + 2xy + y² when x = 13 and y = 7.
- 26.Use (a + b)² = a² + 2ab + b² to find 88².
- 27.Use (a + b)² = a² + 2ab + b² to find 72².
- 28.Use (a − b)² = a² − 2ab + b² to find 35².
- 29.Find the value of x² − y² when x = 3 and y = 2.
- 30.Use a² − b² = (a + b)(a − b) to find 37² − 7².
- 31.Use (a + b)² = a² + 2ab + b² to find 15².
- 32.Use (a − b)² = a² − 2ab + b² to find 11².
- 33.Find the value of x² + 2xy + y² when x = 4 and y = 1.
- 34.Use (a + b)(a − b) = a² − b² to find 84 × 76.
- 35.Use a² − b² = (a + b)(a − b) to find 91² − 31².
- 36.Use (a + b)² = a² + 2ab + b² to find 85².
- 37.Use (a + b)² = a² + 2ab + b² to find 38².
- 38.Use (a + b)(a − b) = a² − b² to find 62 × 58.
- 39.If a − b = 1 and ab = 6, what is a² + b²?
- 40.Find the value of x² − y² when x = 15 and y = 11.
Answer key
- 1632
- 2209
- 120
- 36
- 4624
- 175
- 7
- 448
- 9025
- 3584
- 196
- 3969
- 73
- 1764
- 5476
- 36
- 391
- 63
- 256
- 64
- 25
- 603
- 375
- 2809
- 400
- 7744
- 5184
- 1225
- 5
- 1320
- 225
- 121
- 25
- 6384
- 7320
- 7225
- 1444
- 3596
- 13
- 104
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