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 16².
- 3.Find the value of x² + 2xy + y² when x = 12 and y = 5.
- 4.Use (a + b)(a − b) = a² − b² to find 77 × 63.
- 5.Find the value of x² − y² when x = 13 and y = 4.
- 6.Use (a − b)² = a² − 2ab + b² to find 54².
- 7.Use (a + b)² = a² + 2ab + b² to find 38².
- 8.Use a² − b² = (a + b)(a − b) to find 70² − 38².
- 9.Use (a + b)² = a² + 2ab + b² to find 65².
- 10.Use a² − b² = (a + b)(a − b) to find 60² − 15².
- 11.Find the value of x² + 2xy + y² when x = 4 and y = 1.
- 12.Use a² − b² = (a + b)(a − b) to find 27² − 6².
- 13.Use (a + b)(a − b) = a² − b² to find 65 × 55.
- 14.Use (a − b)² = a² − 2ab + b² to find 87².
- 15.Use (a − b)² = a² − 2ab + b² to find 57².
- 16.Use (a − b)² = a² − 2ab + b² to find 91².
- 17.Use (a + b)(a − b) = a² − b² to find 64 × 56.
- 18.Use (a − b)² = a² − 2ab + b² to find 21².
- 19.Use (a − b)² = a² − 2ab + b² to find 79².
- 20.Use (a − b)² = a² − 2ab + b² to find 11².
- 21.Use (a − b)² = a² − 2ab + b² to find 78².
- 22.Use a² − b² = (a + b)(a − b) to find 37² − 23².
- 23.Use (a − b)² = a² − 2ab + b² to find 19².
- 24.Use (a + b)² = a² + 2ab + b² to find 101².
- 25.Use a² − b² = (a + b)(a − b) to find 29² − 1².
- 26.Use (a − b)² = a² − 2ab + b² to find 69².
- 27.Use (a − b)² = a² − 2ab + b² to find 47².
- 28.If a + b = 13 and ab = 40, what is a² + b²?
- 29.Use a² − b² = (a + b)(a − b) to find 37² − 15².
- 30.Use (a − b)² = a² − 2ab + b² to find 24².
- 31.Find the value of x² + 2xy + y² when x = 15 and y = 13.
- 32.Use (a − b)² = a² − 2ab + b² to find 97².
- 33.Use (a + b)² = a² + 2ab + b² to find 44².
- 34.Use (a + b)(a − b) = a² − b² to find 106 × 94.
- 35.If a + b = 9 and ab = 18, what is a² + b²?
- 36.Use (a + b)(a − b) = a² − b² to find 32 × 28.
- 37.Use (a − b)² = a² − 2ab + b² to find 32².
- 38.Use (a + b)(a − b) = a² − b² to find 46 × 34.
- 39.Find the value of x² − 2xy + y² when x = 3 and y = 2.
- 40.Find the value of x² − 2xy + y² when x = 11 and y = 9.
Answer key
- 2116
- 256
- 289
- 4851
- 153
- 2916
- 1444
- 3456
- 4225
- 3375
- 25
- 693
- 3575
- 7569
- 3249
- 8281
- 3584
- 441
- 6241
- 121
- 6084
- 840
- 361
- 10201
- 840
- 4761
- 2209
- 89
- 1144
- 576
- 784
- 9409
- 1936
- 9964
- 45
- 896
- 1024
- 1564
- 1
- 4
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