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 48².
- 2.Use a² − b² = (a + b)(a − b) to find 96² − 75².
- 3.Use (a + b)(a − b) = a² − b² to find 69 × 51.
- 4.Use a² − b² = (a + b)(a − b) to find 30² − 28².
- 5.Find the value of x² + 2xy + y² when x = 6 and y = 3.
- 6.Find the value of x² − y² when x = 10 and y = 4.
- 7.If a − b = 1 and ab = 110, what is a² + b²?
- 8.Use a² − b² = (a + b)(a − b) to find 69² − 49².
- 9.Use (a + b)(a − b) = a² − b² to find 29 × 11.
- 10.Use (a + b)(a − b) = a² − b² to find 46 × 34.
- 11.Use a² − b² = (a + b)(a − b) to find 33² − 30².
- 12.Find the value of x² + 2xy + y² when x = 13 and y = 12.
- 13.Find the value of x² − y² when x = 12 and y = 4.
- 14.If a + b = 18 and ab = 77, what is a² + b²?
- 15.Use (a + b)² = a² + 2ab + b² to find 92².
- 16.Use (a + b)² = a² + 2ab + b² to find 69².
- 17.Use a² − b² = (a + b)(a − b) to find 62² − 42².
- 18.Use a² − b² = (a + b)(a − b) to find 95² − 89².
- 19.Use (a − b)² = a² − 2ab + b² to find 25².
- 20.Use (a − b)² = a² − 2ab + b² to find 14².
- 21.If a + b = 15 and ab = 50, what is a² + b²?
- 22.Use (a + b)(a − b) = a² − b² to find 31 × 29.
- 23.Use (a + b)(a − b) = a² − b² to find 33 × 27.
- 24.Use (a + b)(a − b) = a² − b² to find 97 × 83.
- 25.Find the value of x² − y² when x = 15 and y = 8.
- 26.If a + b = 17 and ab = 66, what is a² + b²?
- 27.Find the value of x² − y² when x = 5 and y = 4.
- 28.Find the value of x² − 2xy + y² when x = 9 and y = 1.
- 29.Use (a − b)² = a² − 2ab + b² to find 43².
- 30.Use a² − b² = (a + b)(a − b) to find 84² − 26².
- 31.Use (a + b)² = a² + 2ab + b² to find 72².
- 32.Use a² − b² = (a + b)(a − b) to find 20² − 2².
- 33.If a + b = 7 and ab = 12, what is a² + b²?
- 34.Use (a + b)² = a² + 2ab + b² to find 55².
- 35.Use a² − b² = (a + b)(a − b) to find 46² − 31².
- 36.Use (a − b)² = a² − 2ab + b² to find 73².
- 37.Use (a + b)² = a² + 2ab + b² to find 46².
- 38.Use (a − b)² = a² − 2ab + b² to find 41².
- 39.Use (a + b)(a − b) = a² − b² to find 27 × 13.
- 40.Use a² − b² = (a + b)(a − b) to find 40² − 32².
Answer key
- 2304
- 3591
- 3519
- 116
- 81
- 84
- 221
- 2360
- 319
- 1564
- 189
- 625
- 128
- 170
- 8464
- 4761
- 2080
- 1104
- 625
- 196
- 125
- 899
- 891
- 8051
- 161
- 157
- 9
- 64
- 1849
- 6380
- 5184
- 396
- 25
- 3025
- 1155
- 5329
- 2116
- 1681
- 351
- 576
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