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.Find the value of x² + 2xy + y² when x = 10 and y = 7.
- 2.Use (a + b)² = a² + 2ab + b² to find 72².
- 3.Use (a + b)² = a² + 2ab + b² to find 25².
- 4.Use (a + b)² = a² + 2ab + b² to find 74².
- 5.Use (a − b)² = a² − 2ab + b² to find 86².
- 6.Use (a + b)² = a² + 2ab + b² to find 13².
- 7.Use (a + b)² = a² + 2ab + b² to find 31².
- 8.Use (a − b)² = a² − 2ab + b² to find 23².
- 9.Use a² − b² = (a + b)(a − b) to find 48² − 32².
- 10.Use (a + b)(a − b) = a² − b² to find 62 × 58.
- 11.Use (a + b)² = a² + 2ab + b² to find 108².
- 12.Use (a + b)(a − b) = a² − b² to find 69 × 51.
- 13.Use a² − b² = (a + b)(a − b) to find 39² − 11².
- 14.Use (a + b)² = a² + 2ab + b² to find 29².
- 15.Find the value of x² − y² when x = 13 and y = 5.
- 16.If a + b = 10 and ab = 9, what is a² + b²?
- 17.Use (a − b)² = a² − 2ab + b² to find 28².
- 18.Use a² − b² = (a + b)(a − b) to find 58² − 44².
- 19.Use (a + b)(a − b) = a² − b² to find 74 × 66.
- 20.Use (a + b)(a − b) = a² − b² to find 55 × 45.
- 21.Use (a − b)² = a² − 2ab + b² to find 29².
- 22.Use (a + b)(a − b) = a² − b² to find 81 × 79.
- 23.Use (a − b)² = a² − 2ab + b² to find 66².
- 24.Use (a + b)(a − b) = a² − b² to find 108 × 92.
- 25.Use (a + b)² = a² + 2ab + b² to find 56².
- 26.Find the value of x² − 2xy + y² when x = 9 and y = 1.
- 27.Use (a + b)² = a² + 2ab + b² to find 62².
- 28.If a − b = 1 and ab = 2, what is a² + b²?
- 29.If a + b = 5 and ab = 6, what is a² + b²?
- 30.Use (a − b)² = a² − 2ab + b² to find 45².
- 31.If a − b = 1 and ab = 30, what is a² + b²?
- 32.Use a² − b² = (a + b)(a − b) to find 76² − 63².
- 33.Use (a + b)(a − b) = a² − b² to find 35 × 25.
- 34.If a − b = 3 and ab = 88, what is a² + b²?
- 35.Use (a − b)² = a² − 2ab + b² to find 33².
- 36.Use (a + b)(a − b) = a² − b² to find 102 × 98.
- 37.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 38.Find the value of x² − 2xy + y² when x = 15 and y = 12.
- 39.Use a² − b² = (a + b)(a − b) to find 49² − 24².
- 40.If a − b = 1 and ab = 6, what is a² + b²?
Answer key
- 289
- 5184
- 625
- 5476
- 7396
- 169
- 961
- 529
- 1280
- 3596
- 11664
- 3519
- 1400
- 841
- 144
- 82
- 784
- 1428
- 4884
- 2475
- 841
- 6399
- 4356
- 9936
- 3136
- 64
- 3844
- 5
- 13
- 2025
- 61
- 1807
- 875
- 185
- 1089
- 9996
- 1591
- 9
- 1825
- 13
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