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 35².
- 2.Use (a + b)² = a² + 2ab + b² to find 47².
- 3.Use (a − b)² = a² − 2ab + b² to find 36².
- 4.If a + b = 15 and ab = 54, what is a² + b²?
- 5.Use (a + b)² = a² + 2ab + b² to find 39².
- 6.Use (a + b)² = a² + 2ab + b² to find 55².
- 7.Use (a + b)² = a² + 2ab + b² to find 34².
- 8.Find the value of x² − y² when x = 15 and y = 9.
- 9.Use a² − b² = (a + b)(a − b) to find 42² − 32².
- 10.Use (a + b)² = a² + 2ab + b² to find 22².
- 11.Use (a − b)² = a² − 2ab + b² to find 39².
- 12.Use (a − b)² = a² − 2ab + b² to find 43².
- 13.Use (a + b)(a − b) = a² − b² to find 52 × 48.
- 14.Use (a − b)² = a² − 2ab + b² to find 24².
- 15.Use (a + b)(a − b) = a² − b² to find 32 × 28.
- 16.If a + b = 11 and ab = 10, what is a² + b²?
- 17.If a + b = 6 and ab = 8, what is a² + b²?
- 18.Find the value of x² − y² when x = 3 and y = 1.
- 19.Use a² − b² = (a + b)(a − b) to find 60² − 38².
- 20.Use a² − b² = (a + b)(a − b) to find 74² − 1².
- 21.Use (a + b)(a − b) = a² − b² to find 69 × 51.
- 22.If a + b = 9 and ab = 14, what is a² + b²?
- 23.Use (a − b)² = a² − 2ab + b² to find 16².
- 24.Use (a − b)² = a² − 2ab + b² to find 82².
- 25.Use (a + b)² = a² + 2ab + b² to find 67².
- 26.Use (a − b)² = a² − 2ab + b² to find 67².
- 27.Use a² − b² = (a + b)(a − b) to find 44² − 39².
- 28.Use (a + b)² = a² + 2ab + b² to find 92².
- 29.Find the value of x² − 2xy + y² when x = 13 and y = 9.
- 30.Use (a − b)² = a² − 2ab + b² to find 92².
- 31.Use (a + b)² = a² + 2ab + b² to find 15².
- 32.Find the value of x² − y² when x = 7 and y = 6.
- 33.Use a² − b² = (a + b)(a − b) to find 72² − 14².
- 34.Use (a + b)(a − b) = a² − b² to find 74 × 66.
- 35.Find the value of x² + 2xy + y² when x = 4 and y = 2.
- 36.If a − b = 1 and ab = 56, what is a² + b²?
- 37.Use a² − b² = (a + b)(a − b) to find 24² − 11².
- 38.Use a² − b² = (a + b)(a − b) to find 74² − 57².
- 39.Use (a − b)² = a² − 2ab + b² to find 99².
- 40.Use (a + b)² = a² + 2ab + b² to find 38².
Answer key
- 1225
- 2209
- 1296
- 117
- 1521
- 3025
- 1156
- 144
- 740
- 484
- 1521
- 1849
- 2496
- 576
- 896
- 101
- 20
- 8
- 2156
- 5475
- 3519
- 53
- 256
- 6724
- 4489
- 4489
- 415
- 8464
- 16
- 8464
- 225
- 13
- 4988
- 4884
- 36
- 113
- 455
- 2227
- 9801
- 1444
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