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 66² − 38².
- 2.Use a² − b² = (a + b)(a − b) to find 32² − 9².
- 3.Use (a + b)² = a² + 2ab + b² to find 34².
- 4.Use (a + b)(a − b) = a² − b² to find 106 × 94.
- 5.Find the value of x² − 2xy + y² when x = 7 and y = 4.
- 6.Use (a + b)² = a² + 2ab + b² to find 63².
- 7.Use a² − b² = (a + b)(a − b) to find 58² − 18².
- 8.Use (a + b)(a − b) = a² − b² to find 67 × 53.
- 9.Use (a + b)² = a² + 2ab + b² to find 42².
- 10.If a − b = 6 and ab = 72, what is a² + b²?
- 11.Use (a − b)² = a² − 2ab + b² to find 89².
- 12.Use a² − b² = (a + b)(a − b) to find 22² − 3².
- 13.If a − b = 4 and ab = 32, what is a² + b²?
- 14.Use a² − b² = (a + b)(a − b) to find 30² − 29².
- 15.If a − b = 3 and ab = 4, what is a² + b²?
- 16.Use (a + b)² = a² + 2ab + b² to find 58².
- 17.Use (a − b)² = a² − 2ab + b² to find 87².
- 18.Use (a − b)² = a² − 2ab + b² to find 75².
- 19.Use (a − b)² = a² − 2ab + b² to find 83².
- 20.Use a² − b² = (a + b)(a − b) to find 38² − 10².
- 21.Use a² − b² = (a + b)(a − b) to find 69² − 64².
- 22.Use (a + b)² = a² + 2ab + b² to find 38².
- 23.Use (a + b)(a − b) = a² − b² to find 109 × 91.
- 24.Use (a − b)² = a² − 2ab + b² to find 71².
- 25.Find the value of x² − y² when x = 7 and y = 5.
- 26.Use (a + b)² = a² + 2ab + b² to find 35².
- 27.If a − b = 8 and ab = 48, what is a² + b²?
- 28.If a − b = 1 and ab = 110, what is a² + b²?
- 29.Use (a + b)² = a² + 2ab + b² to find 47².
- 30.Use (a + b)(a − b) = a² − b² to find 27 × 13.
- 31.Use (a − b)² = a² − 2ab + b² to find 55².
- 32.If a − b = 2 and ab = 24, what is a² + b²?
- 33.Use (a − b)² = a² − 2ab + b² to find 38².
- 34.Use (a − b)² = a² − 2ab + b² to find 68².
- 35.Use a² − b² = (a + b)(a − b) to find 32² − 11².
- 36.Use (a + b)(a − b) = a² − b² to find 64 × 56.
- 37.Use (a + b)² = a² + 2ab + b² to find 85².
- 38.Use (a − b)² = a² − 2ab + b² to find 37².
- 39.Use (a + b)² = a² + 2ab + b² to find 21².
- 40.Use (a + b)² = a² + 2ab + b² to find 86².
Answer key
- 2912
- 943
- 1156
- 9964
- 9
- 3969
- 3040
- 3551
- 1764
- 180
- 7921
- 475
- 80
- 59
- 17
- 3364
- 7569
- 5625
- 6889
- 1344
- 665
- 1444
- 9919
- 5041
- 24
- 1225
- 160
- 221
- 2209
- 351
- 3025
- 52
- 1444
- 4624
- 903
- 3584
- 7225
- 1369
- 441
- 7396
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