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)(a − b) = a² − b² to find 33 × 27.
- 2.Use (a − b)² = a² − 2ab + b² to find 14².
- 3.Use a² − b² = (a + b)(a − b) to find 36² − 13².
- 4.Use (a + b)(a − b) = a² − b² to find 34 × 26.
- 5.Use (a − b)² = a² − 2ab + b² to find 97².
- 6.Use (a + b)(a − b) = a² − b² to find 48 × 32.
- 7.Use (a + b)(a − b) = a² − b² to find 67 × 53.
- 8.If a − b = 9 and ab = 36, what is a² + b²?
- 9.Use (a + b)(a − b) = a² − b² to find 79 × 61.
- 10.Use (a − b)² = a² − 2ab + b² to find 49².
- 11.Use (a + b)² = a² + 2ab + b² to find 76².
- 12.Use (a + b)² = a² + 2ab + b² to find 48².
- 13.Use (a − b)² = a² − 2ab + b² to find 12².
- 14.Find the value of x² − y² when x = 15 and y = 12.
- 15.If a − b = 5 and ab = 36, what is a² + b²?
- 16.Use (a − b)² = a² − 2ab + b² to find 39².
- 17.Find the value of x² − y² when x = 4 and y = 3.
- 18.Use (a + b)² = a² + 2ab + b² to find 89².
- 19.Find the value of x² + 2xy + y² when x = 6 and y = 1.
- 20.Use (a + b)(a − b) = a² − b² to find 101 × 99.
- 21.Find the value of x² + 2xy + y² when x = 3 and y = 1.
- 22.Use (a + b)(a − b) = a² − b² to find 56 × 44.
- 23.Use a² − b² = (a + b)(a − b) to find 30² − 21².
- 24.Use (a + b)² = a² + 2ab + b² to find 99².
- 25.Find the value of x² + 2xy + y² when x = 7 and y = 5.
- 26.If a − b = 2 and ab = 80, what is a² + b²?
- 27.Use (a + b)² = a² + 2ab + b² to find 39².
- 28.Use (a − b)² = a² − 2ab + b² to find 67².
- 29.Use (a + b)² = a² + 2ab + b² to find 13².
- 30.Find the value of x² + 2xy + y² when x = 14 and y = 4.
- 31.Find the value of x² − 2xy + y² when x = 13 and y = 7.
- 32.Use a² − b² = (a + b)(a − b) to find 35² − 29².
- 33.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 34.Use (a + b)(a − b) = a² − b² to find 89 × 71.
- 35.Use (a − b)² = a² − 2ab + b² to find 38².
- 36.Use (a − b)² = a² − 2ab + b² to find 33².
- 37.Use a² − b² = (a + b)(a − b) to find 53² − 48².
- 38.Use (a + b)² = a² + 2ab + b² to find 26².
- 39.Use (a − b)² = a² − 2ab + b² to find 37².
- 40.Use (a − b)² = a² − 2ab + b² to find 85².
Answer key
- 891
- 196
- 1127
- 884
- 9409
- 1536
- 3551
- 153
- 4819
- 2401
- 5776
- 2304
- 144
- 81
- 97
- 1521
- 7
- 7921
- 49
- 9999
- 16
- 2464
- 459
- 9801
- 144
- 164
- 1521
- 4489
- 169
- 324
- 36
- 384
- 1591
- 6319
- 1444
- 1089
- 505
- 676
- 1369
- 7225
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