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 = 3 and y = 2.
- 2.Use (a + b)(a − b) = a² − b² to find 62 × 58.
- 3.If a + b = 7 and ab = 12, what is a² + b²?
- 4.Use (a + b)(a − b) = a² − b² to find 64 × 56.
- 5.If a + b = 12 and ab = 27, what is a² + b²?
- 6.If a − b = 3 and ab = 10, what is a² + b²?
- 7.Use a² − b² = (a + b)(a − b) to find 63² − 57².
- 8.Use (a + b)² = a² + 2ab + b² to find 52².
- 9.Use (a + b)² = a² + 2ab + b² to find 76².
- 10.Use (a − b)² = a² − 2ab + b² to find 72².
- 11.If a − b = 6 and ab = 7, what is a² + b²?
- 12.Use (a + b)² = a² + 2ab + b² to find 97².
- 13.Use (a − b)² = a² − 2ab + b² to find 29².
- 14.Use (a + b)² = a² + 2ab + b² to find 56².
- 15.Use (a − b)² = a² − 2ab + b² to find 53².
- 16.Find the value of x² − 2xy + y² when x = 12 and y = 7.
- 17.Use (a − b)² = a² − 2ab + b² to find 58².
- 18.If a − b = 9 and ab = 22, what is a² + b²?
- 19.Find the value of x² − y² when x = 12 and y = 10.
- 20.Use a² − b² = (a + b)(a − b) to find 25² − 19².
- 21.Use (a − b)² = a² − 2ab + b² to find 85².
- 22.Use (a + b)² = a² + 2ab + b² to find 85².
- 23.Use (a + b)² = a² + 2ab + b² to find 12².
- 24.Use (a − b)² = a² − 2ab + b² to find 37².
- 25.Use a² − b² = (a + b)(a − b) to find 20² − 1².
- 26.Use (a − b)² = a² − 2ab + b² to find 28².
- 27.Use (a − b)² = a² − 2ab + b² to find 69².
- 28.Use (a + b)(a − b) = a² − b² to find 108 × 92.
- 29.Use (a + b)(a − b) = a² − b² to find 22 × 18.
- 30.Use (a + b)(a − b) = a² − b² to find 73 × 67.
- 31.Find the value of x² + 2xy + y² when x = 10 and y = 3.
- 32.Use (a − b)² = a² − 2ab + b² to find 34².
- 33.Use (a − b)² = a² − 2ab + b² to find 76².
- 34.Find the value of x² − y² when x = 13 and y = 3.
- 35.Use (a − b)² = a² − 2ab + b² to find 17².
- 36.Use (a + b)² = a² + 2ab + b² to find 89².
- 37.Use (a + b)(a − b) = a² − b² to find 96 × 84.
- 38.Use (a + b)(a − b) = a² − b² to find 104 × 96.
- 39.Use a² − b² = (a + b)(a − b) to find 64² − 48².
- 40.Find the value of x² − 2xy + y² when x = 9 and y = 4.
Answer key
- 25
- 3596
- 25
- 3584
- 90
- 29
- 720
- 2704
- 5776
- 5184
- 50
- 9409
- 841
- 3136
- 2809
- 25
- 3364
- 125
- 44
- 264
- 7225
- 7225
- 144
- 1369
- 399
- 784
- 4761
- 9936
- 396
- 4891
- 169
- 1156
- 5776
- 160
- 289
- 7921
- 8064
- 9984
- 1792
- 25
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