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 41².
- 2.Use (a + b)² = a² + 2ab + b² to find 55².
- 3.Find the value of x² − y² when x = 14 and y = 8.
- 4.Use (a + b)(a − b) = a² − b² to find 33 × 27.
- 5.Use (a + b)² = a² + 2ab + b² to find 96².
- 6.Use (a + b)(a − b) = a² − b² to find 61 × 59.
- 7.Use (a + b)(a − b) = a² − b² to find 99 × 81.
- 8.Use (a + b)² = a² + 2ab + b² to find 71².
- 9.Find the value of x² + 2xy + y² when x = 6 and y = 3.
- 10.Use a² − b² = (a + b)(a − b) to find 87² − 61².
- 11.Use (a + b)(a − b) = a² − b² to find 101 × 99.
- 12.Use (a + b)² = a² + 2ab + b² to find 79².
- 13.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 14.Use (a + b)² = a² + 2ab + b² to find 61².
- 15.Use (a − b)² = a² − 2ab + b² to find 66².
- 16.Use (a + b)(a − b) = a² − b² to find 94 × 86.
- 17.Find the value of x² − 2xy + y² when x = 15 and y = 12.
- 18.Use (a + b)(a − b) = a² − b² to find 24 × 16.
- 19.Use a² − b² = (a + b)(a − b) to find 98² − 54².
- 20.Use (a + b)(a − b) = a² − b² to find 85 × 75.
- 21.Use (a − b)² = a² − 2ab + b² to find 37².
- 22.If a − b = 1 and ab = 90, what is a² + b²?
- 23.Find the value of x² − 2xy + y² when x = 10 and y = 7.
- 24.Use a² − b² = (a + b)(a − b) to find 41² − 6².
- 25.Use a² − b² = (a + b)(a − b) to find 80² − 56².
- 26.Use (a + b)(a − b) = a² − b² to find 65 × 55.
- 27.Find the value of x² − y² when x = 5 and y = 2.
- 28.Find the value of x² + 2xy + y² when x = 13 and y = 11.
- 29.If a + b = 12 and ab = 32, what is a² + b²?
- 30.Use (a + b)² = a² + 2ab + b² to find 45².
- 31.Use (a + b)(a − b) = a² − b² to find 78 × 62.
- 32.Use (a + b)(a − b) = a² − b² to find 38 × 22.
- 33.Use (a + b)² = a² + 2ab + b² to find 98².
- 34.If a − b = 3 and ab = 4, what is a² + b²?
- 35.Use a² − b² = (a + b)(a − b) to find 48² − 43².
- 36.Use (a + b)² = a² + 2ab + b² to find 78².
- 37.Use a² − b² = (a + b)(a − b) to find 78² − 13².
- 38.Use (a − b)² = a² − 2ab + b² to find 27².
- 39.Use (a + b)(a − b) = a² − b² to find 92 × 88.
- 40.Use a² − b² = (a + b)(a − b) to find 37² − 32².
Answer key
- 1681
- 3025
- 132
- 891
- 9216
- 3599
- 8019
- 5041
- 81
- 3848
- 9999
- 6241
- 1536
- 3721
- 4356
- 8084
- 9
- 384
- 6688
- 6375
- 1369
- 181
- 9
- 1645
- 3264
- 3575
- 21
- 576
- 80
- 2025
- 4836
- 836
- 9604
- 17
- 455
- 6084
- 5915
- 729
- 8096
- 345
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