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 46².
- 2.Use (a + b)² = a² + 2ab + b² to find 59².
- 3.Use a² − b² = (a + b)(a − b) to find 93² − 29².
- 4.Use (a − b)² = a² − 2ab + b² to find 69².
- 5.If a + b = 13 and ab = 12, what is a² + b²?
- 6.Use (a − b)² = a² − 2ab + b² to find 34².
- 7.Use (a − b)² = a² − 2ab + b² to find 61².
- 8.Use (a + b)(a − b) = a² − b² to find 69 × 51.
- 9.Use (a + b)(a − b) = a² − b² to find 23 × 17.
- 10.Find the value of x² + 2xy + y² when x = 14 and y = 7.
- 11.Use a² − b² = (a + b)(a − b) to find 85² − 33².
- 12.Use (a − b)² = a² − 2ab + b² to find 92².
- 13.If a − b = 3 and ab = 10, what is a² + b²?
- 14.Use (a + b)² = a² + 2ab + b² to find 39².
- 15.Find the value of x² + 2xy + y² when x = 10 and y = 1.
- 16.Find the value of x² − y² when x = 13 and y = 3.
- 17.Find the value of x² − 2xy + y² when x = 4 and y = 3.
- 18.If a + b = 9 and ab = 18, what is a² + b²?
- 19.Use a² − b² = (a + b)(a − b) to find 49² − 45².
- 20.Use (a − b)² = a² − 2ab + b² to find 85².
- 21.If a − b = 1 and ab = 42, what is a² + b²?
- 22.Use (a + b)(a − b) = a² − b² to find 68 × 52.
- 23.Find the value of x² + 2xy + y² when x = 15 and y = 3.
- 24.Use a² − b² = (a + b)(a − b) to find 76² − 75².
- 25.If a − b = 6 and ab = 27, what is a² + b²?
- 26.Use a² − b² = (a + b)(a − b) to find 81² − 12².
- 27.Find the value of x² − y² when x = 9 and y = 8.
- 28.Use (a + b)(a − b) = a² − b² to find 32 × 28.
- 29.Use (a + b)(a − b) = a² − b² to find 27 × 13.
- 30.Use a² − b² = (a + b)(a − b) to find 70² − 14².
- 31.If a + b = 15 and ab = 36, what is a² + b²?
- 32.Find the value of x² + 2xy + y² when x = 4 and y = 2.
- 33.Use (a − b)² = a² − 2ab + b² to find 39².
- 34.Use a² − b² = (a + b)(a − b) to find 38² − 10².
- 35.Find the value of x² − y² when x = 8 and y = 3.
- 36.Use (a + b)(a − b) = a² − b² to find 57 × 43.
- 37.Use (a + b)(a − b) = a² − b² to find 107 × 93.
- 38.Use a² − b² = (a + b)(a − b) to find 84² − 60².
- 39.Use (a + b)² = a² + 2ab + b² to find 83².
- 40.Use (a − b)² = a² − 2ab + b² to find 67².
Answer key
- 2116
- 3481
- 7808
- 4761
- 145
- 1156
- 3721
- 3519
- 391
- 441
- 6136
- 8464
- 29
- 1521
- 121
- 160
- 1
- 45
- 376
- 7225
- 85
- 3536
- 324
- 151
- 90
- 6417
- 17
- 896
- 351
- 4704
- 153
- 36
- 1521
- 1344
- 55
- 2451
- 9951
- 3456
- 6889
- 4489
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