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 48 × 32.
- 2.Use (a + b)(a − b) = a² − b² to find 37 × 23.
- 3.Use (a + b)² = a² + 2ab + b² to find 12².
- 4.Use (a + b)(a − b) = a² − b² to find 28 × 12.
- 5.Find the value of x² − 2xy + y² when x = 3 and y = 1.
- 6.Use (a − b)² = a² − 2ab + b² to find 55².
- 7.Find the value of x² + 2xy + y² when x = 9 and y = 1.
- 8.Use (a + b)² = a² + 2ab + b² to find 19².
- 9.Use (a + b)² = a² + 2ab + b² to find 97².
- 10.Find the value of x² − 2xy + y² when x = 13 and y = 1.
- 11.Use (a + b)² = a² + 2ab + b² to find 83².
- 12.Use a² − b² = (a + b)(a − b) to find 84² − 45².
- 13.Find the value of x² − y² when x = 8 and y = 4.
- 14.Use (a + b)(a − b) = a² − b² to find 42 × 38.
- 15.Use (a − b)² = a² − 2ab + b² to find 49².
- 16.Use (a − b)² = a² − 2ab + b² to find 29².
- 17.Use (a − b)² = a² − 2ab + b² to find 79².
- 18.Use (a + b)² = a² + 2ab + b² to find 89².
- 19.Use a² − b² = (a + b)(a − b) to find 34² − 16².
- 20.If a − b = 2 and ab = 35, what is a² + b²?
- 21.Use a² − b² = (a + b)(a − b) to find 56² − 7².
- 22.If a + b = 7 and ab = 12, what is a² + b²?
- 23.If a + b = 3 and ab = 2, what is a² + b²?
- 24.Use (a + b)² = a² + 2ab + b² to find 43².
- 25.Use (a − b)² = a² − 2ab + b² to find 91².
- 26.Use (a + b)(a − b) = a² − b² to find 53 × 47.
- 27.If a − b = 8 and ab = 20, what is a² + b²?
- 28.Find the value of x² − 2xy + y² when x = 4 and y = 3.
- 29.Use a² − b² = (a + b)(a − b) to find 78² − 38².
- 30.Use (a + b)(a − b) = a² − b² to find 82 × 78.
- 31.If a − b = 1 and ab = 2, what is a² + b²?
- 32.If a − b = 2 and ab = 8, what is a² + b²?
- 33.Use (a − b)² = a² − 2ab + b² to find 19².
- 34.Use a² − b² = (a + b)(a − b) to find 26² − 5².
- 35.Use (a + b)(a − b) = a² − b² to find 64 × 56.
- 36.Find the value of x² − 2xy + y² when x = 10 and y = 4.
- 37.Find the value of x² − y² when x = 10 and y = 4.
- 38.Use a² − b² = (a + b)(a − b) to find 32² − 22².
- 39.Use (a + b)² = a² + 2ab + b² to find 53².
- 40.If a − b = 6 and ab = 40, what is a² + b²?
Answer key
- 1536
- 851
- 144
- 336
- 4
- 3025
- 100
- 361
- 9409
- 144
- 6889
- 5031
- 48
- 1596
- 2401
- 841
- 6241
- 7921
- 900
- 74
- 3087
- 25
- 5
- 1849
- 8281
- 2491
- 104
- 1
- 4640
- 6396
- 5
- 20
- 361
- 651
- 3584
- 36
- 84
- 540
- 2809
- 116
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