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 31 × 29.
- 2.Find the value of x² − 2xy + y² when x = 4 and y = 1.
- 3.Use (a − b)² = a² − 2ab + b² to find 13².
- 4.Use (a − b)² = a² − 2ab + b² to find 29².
- 5.Use a² − b² = (a + b)(a − b) to find 45² − 9².
- 6.Find the value of x² − 2xy + y² when x = 9 and y = 7.
- 7.Use a² − b² = (a + b)(a − b) to find 71² − 46².
- 8.Find the value of x² − 2xy + y² when x = 5 and y = 4.
- 9.If a + b = 17 and ab = 72, what is a² + b²?
- 10.Use (a − b)² = a² − 2ab + b² to find 81².
- 11.Use a² − b² = (a + b)(a − b) to find 96² − 6².
- 12.Find the value of x² − 2xy + y² when x = 3 and y = 2.
- 13.If a − b = 11 and ab = 12, what is a² + b²?
- 14.If a + b = 3 and ab = 2, what is a² + b²?
- 15.Find the value of x² + 2xy + y² when x = 4 and y = 3.
- 16.Use a² − b² = (a + b)(a − b) to find 25² − 5².
- 17.Use (a + b)² = a² + 2ab + b² to find 13².
- 18.Use (a + b)² = a² + 2ab + b² to find 67².
- 19.Use (a + b)(a − b) = a² − b² to find 37 × 23.
- 20.Find the value of x² + 2xy + y² when x = 14 and y = 3.
- 21.Use (a + b)(a − b) = a² − b² to find 51 × 49.
- 22.Use a² − b² = (a + b)(a − b) to find 43² − 36².
- 23.Use a² − b² = (a + b)(a − b) to find 37² − 32².
- 24.Use (a + b)² = a² + 2ab + b² to find 93².
- 25.Use a² − b² = (a + b)(a − b) to find 57² − 7².
- 26.Use a² − b² = (a + b)(a − b) to find 79² − 12².
- 27.Use (a − b)² = a² − 2ab + b² to find 83².
- 28.Use a² − b² = (a + b)(a − b) to find 85² − 27².
- 29.Find the value of x² + 2xy + y² when x = 6 and y = 3.
- 30.Use (a + b)² = a² + 2ab + b² to find 92².
- 31.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 32.Find the value of x² − y² when x = 9 and y = 5.
- 33.Use (a + b)(a − b) = a² − b² to find 44 × 36.
- 34.Use (a − b)² = a² − 2ab + b² to find 88².
- 35.Use (a + b)(a − b) = a² − b² to find 71 × 69.
- 36.If a + b = 14 and ab = 48, what is a² + b²?
- 37.Use (a − b)² = a² − 2ab + b² to find 46².
- 38.Use a² − b² = (a + b)(a − b) to find 70² − 10².
- 39.Use (a + b)(a − b) = a² − b² to find 24 × 16.
- 40.Find the value of x² − y² when x = 15 and y = 13.
Answer key
- 899
- 9
- 169
- 841
- 1944
- 4
- 2925
- 1
- 145
- 6561
- 9180
- 1
- 145
- 5
- 49
- 600
- 169
- 4489
- 851
- 289
- 2499
- 553
- 345
- 8649
- 3200
- 6097
- 6889
- 6496
- 81
- 8464
- 8091
- 56
- 1584
- 7744
- 4899
- 100
- 2116
- 4800
- 384
- 56
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