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 a² − b² = (a + b)(a − b) to find 64² − 13².
- 2.Use (a + b)² = a² + 2ab + b² to find 69².
- 3.Use (a + b)² = a² + 2ab + b² to find 33².
- 4.Use (a + b)(a − b) = a² − b² to find 92 × 88.
- 5.Use (a + b)² = a² + 2ab + b² to find 13².
- 6.Use (a − b)² = a² − 2ab + b² to find 83².
- 7.Use (a + b)² = a² + 2ab + b² to find 37².
- 8.Find the value of x² + 2xy + y² when x = 8 and y = 7.
- 9.Use (a + b)(a − b) = a² − b² to find 67 × 53.
- 10.Use a² − b² = (a + b)(a − b) to find 90² − 65².
- 11.Find the value of x² − y² when x = 11 and y = 10.
- 12.Use (a + b)(a − b) = a² − b² to find 74 × 66.
- 13.Use (a + b)(a − b) = a² − b² to find 69 × 51.
- 14.Use (a − b)² = a² − 2ab + b² to find 15².
- 15.Use (a − b)² = a² − 2ab + b² to find 98².
- 16.If a + b = 18 and ab = 77, what is a² + b²?
- 17.Use (a + b)² = a² + 2ab + b² to find 88².
- 18.Use (a + b)(a − b) = a² − b² to find 58 × 42.
- 19.If a + b = 10 and ab = 16, what is a² + b²?
- 20.Use a² − b² = (a + b)(a − b) to find 60² − 17².
- 21.Use (a − b)² = a² − 2ab + b² to find 68².
- 22.Use a² − b² = (a + b)(a − b) to find 28² − 19².
- 23.Use a² − b² = (a + b)(a − b) to find 42² − 30².
- 24.Use (a + b)² = a² + 2ab + b² to find 87².
- 25.If a − b = 2 and ab = 3, what is a² + b²?
- 26.Use a² − b² = (a + b)(a − b) to find 54² − 49².
- 27.Use (a + b)² = a² + 2ab + b² to find 41².
- 28.If a − b = 8 and ab = 48, what is a² + b²?
- 29.Use (a + b)² = a² + 2ab + b² to find 106².
- 30.Use (a + b)(a − b) = a² − b² to find 61 × 59.
- 31.Use (a − b)² = a² − 2ab + b² to find 45².
- 32.Use a² − b² = (a + b)(a − b) to find 94² − 82².
- 33.If a − b = 4 and ab = 5, what is a² + b²?
- 34.Use (a + b)² = a² + 2ab + b² to find 12².
- 35.Use a² − b² = (a + b)(a − b) to find 88² − 55².
- 36.Use (a − b)² = a² − 2ab + b² to find 53².
- 37.Use (a + b)(a − b) = a² − b² to find 29 × 11.
- 38.If a + b = 9 and ab = 14, what is a² + b²?
- 39.If a − b = 2 and ab = 35, what is a² + b²?
- 40.Use (a + b)² = a² + 2ab + b² to find 14².
Answer key
- 3927
- 4761
- 1089
- 8096
- 169
- 6889
- 1369
- 225
- 3551
- 3875
- 21
- 4884
- 3519
- 225
- 9604
- 170
- 7744
- 2436
- 68
- 3311
- 4624
- 423
- 864
- 7569
- 10
- 515
- 1681
- 160
- 11236
- 3599
- 2025
- 2112
- 26
- 144
- 4719
- 2809
- 319
- 53
- 74
- 196
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