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.Find the value of x² − y² when x = 12 and y = 2.
- 2.Use (a + b)(a − b) = a² − b² to find 29 × 11.
- 3.If a − b = 10 and ab = 11, what is a² + b²?
- 4.Use (a − b)² = a² − 2ab + b² to find 75².
- 5.Use (a − b)² = a² − 2ab + b² to find 87².
- 6.Use (a + b)² = a² + 2ab + b² to find 33².
- 7.If a − b = 1 and ab = 12, what is a² + b²?
- 8.If a − b = 5 and ab = 66, what is a² + b²?
- 9.Use (a + b)² = a² + 2ab + b² to find 14².
- 10.Find the value of x² − y² when x = 12 and y = 7.
- 11.Find the value of x² − 2xy + y² when x = 12 and y = 11.
- 12.Use (a + b)(a − b) = a² − b² to find 44 × 36.
- 13.Use a² − b² = (a + b)(a − b) to find 98² − 95².
- 14.Use a² − b² = (a + b)(a − b) to find 44² − 9².
- 15.Use (a + b)² = a² + 2ab + b² to find 48².
- 16.Find the value of x² − y² when x = 6 and y = 4.
- 17.Use (a + b)² = a² + 2ab + b² to find 69².
- 18.Find the value of x² + 2xy + y² when x = 10 and y = 3.
- 19.Use a² − b² = (a + b)(a − b) to find 94² − 75².
- 20.Use (a + b)(a − b) = a² − b² to find 107 × 93.
- 21.Use (a + b)(a − b) = a² − b² to find 78 × 62.
- 22.Use (a − b)² = a² − 2ab + b² to find 46².
- 23.If a − b = 1 and ab = 2, what is a² + b²?
- 24.Use a² − b² = (a + b)(a − b) to find 53² − 26².
- 25.Find the value of x² + 2xy + y² when x = 15 and y = 4.
- 26.Find the value of x² − 2xy + y² when x = 13 and y = 6.
- 27.Find the value of x² + 2xy + y² when x = 6 and y = 1.
- 28.Use (a + b)(a − b) = a² − b² to find 53 × 47.
- 29.Use (a + b)² = a² + 2ab + b² to find 13².
- 30.Use (a + b)(a − b) = a² − b² to find 34 × 26.
- 31.Find the value of x² − 2xy + y² when x = 3 and y = 2.
- 32.Use (a + b)(a − b) = a² − b² to find 67 × 53.
- 33.Use (a − b)² = a² − 2ab + b² to find 67².
- 34.Use (a − b)² = a² − 2ab + b² to find 72².
- 35.Find the value of x² − 2xy + y² when x = 12 and y = 10.
- 36.If a + b = 5 and ab = 6, what is a² + b²?
- 37.Find the value of x² − 2xy + y² when x = 13 and y = 7.
- 38.Use (a − b)² = a² − 2ab + b² to find 29².
- 39.Use (a + b)² = a² + 2ab + b² to find 54².
- 40.Use (a + b)² = a² + 2ab + b² to find 47².
Answer key
- 140
- 319
- 122
- 5625
- 7569
- 1089
- 25
- 157
- 196
- 95
- 1
- 1584
- 579
- 1855
- 2304
- 20
- 4761
- 169
- 3211
- 9951
- 4836
- 2116
- 5
- 2133
- 361
- 49
- 49
- 2491
- 169
- 884
- 1
- 3551
- 4489
- 5184
- 4
- 13
- 36
- 841
- 2916
- 2209
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