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 89².
- 2.Find the value of x² − y² when x = 8 and y = 5.
- 3.Find the value of x² − 2xy + y² when x = 8 and y = 6.
- 4.Use (a + b)² = a² + 2ab + b² to find 51².
- 5.Use a² − b² = (a + b)(a − b) to find 24² − 12².
- 6.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 7.Use (a − b)² = a² − 2ab + b² to find 25².
- 8.Use (a + b)² = a² + 2ab + b² to find 89².
- 9.Use (a + b)² = a² + 2ab + b² to find 107².
- 10.Use a² − b² = (a + b)(a − b) to find 62² − 6².
- 11.Find the value of x² − y² when x = 15 and y = 12.
- 12.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 13.Find the value of x² + 2xy + y² when x = 9 and y = 1.
- 14.Find the value of x² − 2xy + y² when x = 10 and y = 2.
- 15.If a + b = 11 and ab = 10, what is a² + b²?
- 16.Use a² − b² = (a + b)(a − b) to find 80² − 51².
- 17.Use a² − b² = (a + b)(a − b) to find 68² − 20².
- 18.Use (a − b)² = a² − 2ab + b² to find 11².
- 19.Use (a + b)² = a² + 2ab + b² to find 11².
- 20.If a + b = 13 and ab = 40, what is a² + b²?
- 21.Use a² − b² = (a + b)(a − b) to find 71² − 3².
- 22.Use (a − b)² = a² − 2ab + b² to find 26².
- 23.If a + b = 16 and ab = 48, what is a² + b²?
- 24.Use (a + b)(a − b) = a² − b² to find 68 × 52.
- 25.Find the value of x² − 2xy + y² when x = 15 and y = 14.
- 26.Use (a + b)² = a² + 2ab + b² to find 94².
- 27.Find the value of x² − 2xy + y² when x = 13 and y = 5.
- 28.Find the value of x² − y² when x = 5 and y = 4.
- 29.Use a² − b² = (a + b)(a − b) to find 57² − 38².
- 30.Find the value of x² + 2xy + y² when x = 7 and y = 6.
- 31.Find the value of x² + 2xy + y² when x = 13 and y = 3.
- 32.Use (a − b)² = a² − 2ab + b² to find 14².
- 33.Use (a − b)² = a² − 2ab + b² to find 52².
- 34.Use (a − b)² = a² − 2ab + b² to find 88².
- 35.Use (a + b)(a − b) = a² − b² to find 31 × 29.
- 36.Use (a + b)(a − b) = a² − b² to find 26 × 14.
- 37.Use (a + b)² = a² + 2ab + b² to find 65².
- 38.Use (a + b)(a − b) = a² − b² to find 21 × 19.
- 39.Use (a + b)(a − b) = a² − b² to find 102 × 98.
- 40.Find the value of x² − y² when x = 5 and y = 2.
Answer key
- 7921
- 39
- 4
- 2601
- 432
- 8091
- 625
- 7921
- 11449
- 3808
- 81
- 1536
- 100
- 64
- 101
- 3799
- 4224
- 121
- 121
- 89
- 5032
- 676
- 160
- 3536
- 1
- 8836
- 64
- 9
- 1805
- 169
- 256
- 196
- 2704
- 7744
- 899
- 364
- 4225
- 399
- 9996
- 21
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