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.
NameDateTime takenScore ___ / 40
- 1.Use a² − b² = (a + b)(a − b) to find 52² − 37².
- 2.Use (a + b)² = a² + 2ab + b² to find 36².
- 3.Find the value of x² + 2xy + y² when x = 8 and y = 1.
- 4.Use (a − b)² = a² − 2ab + b² to find 25².
- 5.Use (a + b)(a − b) = a² − b² to find 32 × 28.
- 6.Use (a − b)² = a² − 2ab + b² to find 58².
- 7.Use (a + b)² = a² + 2ab + b² to find 16².
- 8.Use (a + b)² = a² + 2ab + b² to find 48².
- 9.Use (a − b)² = a² − 2ab + b² to find 32².
- 10.Use (a + b)² = a² + 2ab + b² to find 59².
- 11.Find the value of x² − 2xy + y² when x = 8 and y = 1.
- 12.Use (a − b)² = a² − 2ab + b² to find 72².
- 13.Use (a + b)² = a² + 2ab + b² to find 24².
- 14.Use (a − b)² = a² − 2ab + b² to find 51².
- 15.Use (a − b)² = a² − 2ab + b² to find 69².
- 16.Use (a − b)² = a² − 2ab + b² to find 31².
- 17.Use (a + b)(a − b) = a² − b² to find 21 × 19.
- 18.Find the value of x² + 2xy + y² when x = 14 and y = 10.
- 19.Find the value of x² − 2xy + y² when x = 5 and y = 2.
- 20.Use a² − b² = (a + b)(a − b) to find 64² − 61².
- 21.Use (a + b)² = a² + 2ab + b² to find 28².
- 22.Use a² − b² = (a + b)(a − b) to find 82² − 23².
- 23.Use a² − b² = (a + b)(a − b) to find 86² − 27².
- 24.Use a² − b² = (a + b)(a − b) to find 80² − 35².
- 25.If a + b = 13 and ab = 30, what is a² + b²?
- 26.Use (a + b)² = a² + 2ab + b² to find 88².
- 27.Find the value of x² − y² when x = 8 and y = 3.
- 28.Find the value of x² − y² when x = 13 and y = 7.
- 29.Use (a − b)² = a² − 2ab + b² to find 88².
- 30.Use (a − b)² = a² − 2ab + b² to find 59².
- 31.Use (a + b)² = a² + 2ab + b² to find 57².
- 32.Use (a − b)² = a² − 2ab + b² to find 61².
- 33.Use (a + b)² = a² + 2ab + b² to find 69².
- 34.Use (a − b)² = a² − 2ab + b² to find 75².
- 35.Use a² − b² = (a + b)(a − b) to find 66² − 31².
- 36.Use a² − b² = (a + b)(a − b) to find 64² − 38².
- 37.Use (a − b)² = a² − 2ab + b² to find 18².
- 38.Use (a − b)² = a² − 2ab + b² to find 52².
- 39.Find the value of x² − 2xy + y² when x = 13 and y = 9.
- 40.If a + b = 9 and ab = 20, what is a² + b²?
Answer key
- 1335
- 1296
- 81
- 625
- 896
- 3364
- 256
- 2304
- 1024
- 3481
- 49
- 5184
- 576
- 2601
- 4761
- 961
- 399
- 576
- 9
- 375
- 784
- 6195
- 6667
- 5175
- 109
- 7744
- 55
- 120
- 7744
- 3481
- 3249
- 3721
- 4761
- 5625
- 3395
- 2652
- 324
- 2704
- 16
- 41
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