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 46².
- 2.Use (a − b)² = a² − 2ab + b² to find 48².
- 3.Use (a + b)² = a² + 2ab + b² to find 43².
- 4.Find the value of x² − 2xy + y² when x = 9 and y = 2.
- 5.Use (a − b)² = a² − 2ab + b² to find 93².
- 6.Use (a + b)² = a² + 2ab + b² to find 45².
- 7.If a + b = 7 and ab = 12, what is a² + b²?
- 8.Use a² − b² = (a + b)(a − b) to find 48² − 36².
- 9.Use (a + b)(a − b) = a² − b² to find 28 × 12.
- 10.Use a² − b² = (a + b)(a − b) to find 57² − 10².
- 11.Use (a − b)² = a² − 2ab + b² to find 42².
- 12.If a − b = 3 and ab = 54, what is a² + b²?
- 13.If a + b = 9 and ab = 14, what is a² + b²?
- 14.If a − b = 3 and ab = 4, what is a² + b²?
- 15.Use (a − b)² = a² − 2ab + b² to find 26².
- 16.Use (a − b)² = a² − 2ab + b² to find 27².
- 17.Use (a + b)(a − b) = a² − b² to find 34 × 26.
- 18.If a + b = 10 and ab = 24, what is a² + b²?
- 19.Use (a + b)² = a² + 2ab + b² to find 54².
- 20.Find the value of x² − y² when x = 12 and y = 1.
- 21.If a − b = 7 and ab = 30, what is a² + b²?
- 22.Use (a + b)(a − b) = a² − b² to find 72 × 68.
- 23.Use (a − b)² = a² − 2ab + b² to find 57².
- 24.Use (a + b)(a − b) = a² − b² to find 56 × 44.
- 25.Find the value of x² − y² when x = 6 and y = 1.
- 26.Use (a + b)(a − b) = a² − b² to find 76 × 64.
- 27.Find the value of x² + 2xy + y² when x = 5 and y = 4.
- 28.If a − b = 2 and ab = 80, what is a² + b²?
- 29.Use (a + b)² = a² + 2ab + b² to find 49².
- 30.Use a² − b² = (a + b)(a − b) to find 37² − 15².
- 31.Use a² − b² = (a + b)(a − b) to find 26² − 1².
- 32.Use (a + b)² = a² + 2ab + b² to find 16².
- 33.Use a² − b² = (a + b)(a − b) to find 22² − 14².
- 34.Use (a + b)² = a² + 2ab + b² to find 48².
- 35.If a + b = 16 and ab = 48, what is a² + b²?
- 36.Find the value of x² + 2xy + y² when x = 13 and y = 4.
- 37.Use (a − b)² = a² − 2ab + b² to find 31².
- 38.Find the value of x² + 2xy + y² when x = 8 and y = 5.
- 39.Use a² − b² = (a + b)(a − b) to find 39² − 8².
- 40.Find the value of x² − 2xy + y² when x = 15 and y = 7.
Answer key
- 2116
- 2304
- 1849
- 49
- 8649
- 2025
- 25
- 1008
- 336
- 3149
- 1764
- 117
- 53
- 17
- 676
- 729
- 884
- 52
- 2916
- 143
- 109
- 4896
- 3249
- 2464
- 35
- 4864
- 81
- 164
- 2401
- 1144
- 675
- 256
- 288
- 2304
- 160
- 289
- 961
- 169
- 1457
- 64
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