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 86².
- 2.Use a² − b² = (a + b)(a − b) to find 84² − 59².
- 3.If a − b = 3 and ab = 10, what is a² + b²?
- 4.Use (a − b)² = a² − 2ab + b² to find 31².
- 5.If a − b = 4 and ab = 21, what is a² + b²?
- 6.Use (a − b)² = a² − 2ab + b² to find 97².
- 7.Use (a + b)² = a² + 2ab + b² to find 34².
- 8.If a − b = 1 and ab = 42, what is a² + b²?
- 9.Use a² − b² = (a + b)(a − b) to find 94² − 80².
- 10.If a − b = 6 and ab = 16, what is a² + b²?
- 11.Use (a − b)² = a² − 2ab + b² to find 29².
- 12.Use (a + b)(a − b) = a² − b² to find 57 × 43.
- 13.Find the value of x² − 2xy + y² when x = 10 and y = 5.
- 14.Find the value of x² − 2xy + y² when x = 6 and y = 3.
- 15.If a − b = 6 and ab = 40, what is a² + b²?
- 16.Use (a − b)² = a² − 2ab + b² to find 45².
- 17.Use (a − b)² = a² − 2ab + b² to find 81².
- 18.Use (a + b)(a − b) = a² − b² to find 39 × 21.
- 19.Find the value of x² − y² when x = 4 and y = 1.
- 20.Use a² − b² = (a + b)(a − b) to find 74² − 53².
- 21.If a − b = 1 and ab = 2, what is a² + b²?
- 22.If a − b = 7 and ab = 8, what is a² + b²?
- 23.Find the value of x² + 2xy + y² when x = 11 and y = 8.
- 24.Use a² − b² = (a + b)(a − b) to find 27² − 14².
- 25.Use (a − b)² = a² − 2ab + b² to find 69².
- 26.If a + b = 3 and ab = 2, what is a² + b²?
- 27.If a − b = 5 and ab = 50, what is a² + b²?
- 28.Use (a − b)² = a² − 2ab + b² to find 53².
- 29.Use (a + b)(a − b) = a² − b² to find 29 × 11.
- 30.Use (a + b)² = a² + 2ab + b² to find 45².
- 31.If a − b = 1 and ab = 12, what is a² + b²?
- 32.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 33.Find the value of x² − 2xy + y² when x = 9 and y = 4.
- 34.Use (a + b)² = a² + 2ab + b² to find 76².
- 35.Use (a + b)² = a² + 2ab + b² to find 12².
- 36.Use (a + b)² = a² + 2ab + b² to find 71².
- 37.Find the value of x² + 2xy + y² when x = 14 and y = 12.
- 38.Use a² − b² = (a + b)(a − b) to find 24² − 3².
- 39.Use (a + b)² = a² + 2ab + b² to find 106².
- 40.Use a² − b² = (a + b)(a − b) to find 62² − 17².
Answer key
- 7396
- 3575
- 29
- 961
- 58
- 9409
- 1156
- 85
- 2436
- 68
- 841
- 2451
- 25
- 9
- 116
- 2025
- 6561
- 819
- 15
- 2667
- 5
- 65
- 361
- 533
- 4761
- 5
- 125
- 2809
- 319
- 2025
- 25
- 1599
- 25
- 5776
- 144
- 5041
- 676
- 567
- 11236
- 3555
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