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 a² − b² = (a + b)(a − b) to find 94² − 37².
- 2.If a + b = 14 and ab = 48, what is a² + b²?
- 3.Use (a − b)² = a² − 2ab + b² to find 47².
- 4.Use (a − b)² = a² − 2ab + b² to find 87².
- 5.Find the value of x² + 2xy + y² when x = 3 and y = 2.
- 6.If a + b = 12 and ab = 35, what is a² + b²?
- 7.If a − b = 6 and ab = 55, what is a² + b²?
- 8.Use a² − b² = (a + b)(a − b) to find 26² − 8².
- 9.Find the value of x² + 2xy + y² when x = 5 and y = 1.
- 10.Use (a − b)² = a² − 2ab + b² to find 45².
- 11.If a + b = 20 and ab = 96, what is a² + b²?
- 12.Use a² − b² = (a + b)(a − b) to find 97² − 96².
- 13.Use (a + b)(a − b) = a² − b² to find 74 × 66.
- 14.Use (a − b)² = a² − 2ab + b² to find 95².
- 15.Find the value of x² + 2xy + y² when x = 13 and y = 3.
- 16.Use (a + b)² = a² + 2ab + b² to find 45².
- 17.Use (a − b)² = a² − 2ab + b² to find 25².
- 18.Find the value of x² + 2xy + y² when x = 14 and y = 11.
- 19.Find the value of x² + 2xy + y² when x = 10 and y = 3.
- 20.Find the value of x² + 2xy + y² when x = 15 and y = 1.
- 21.If a − b = 11 and ab = 12, what is a² + b²?
- 22.If a + b = 6 and ab = 8, what is a² + b²?
- 23.If a + b = 11 and ab = 10, what is a² + b²?
- 24.Use (a − b)² = a² − 2ab + b² to find 56².
- 25.If a − b = 10 and ab = 24, what is a² + b²?
- 26.Use (a + b)² = a² + 2ab + b² to find 71².
- 27.Use a² − b² = (a + b)(a − b) to find 41² − 17².
- 28.Use (a + b)² = a² + 2ab + b² to find 16².
- 29.Use a² − b² = (a + b)(a − b) to find 36² − 18².
- 30.Find the value of x² + 2xy + y² when x = 4 and y = 2.
- 31.Use (a + b)² = a² + 2ab + b² to find 76².
- 32.Use (a − b)² = a² − 2ab + b² to find 16².
- 33.Use (a − b)² = a² − 2ab + b² to find 65².
- 34.Use (a − b)² = a² − 2ab + b² to find 28².
- 35.Find the value of x² − 2xy + y² when x = 10 and y = 6.
- 36.Use (a + b)² = a² + 2ab + b² to find 26².
- 37.Find the value of x² + 2xy + y² when x = 4 and y = 1.
- 38.Use (a + b)(a − b) = a² − b² to find 106 × 94.
- 39.Use a² − b² = (a + b)(a − b) to find 36² − 26².
- 40.Use (a + b)² = a² + 2ab + b² to find 17².
Answer key
- 7467
- 100
- 2209
- 7569
- 25
- 74
- 146
- 612
- 36
- 2025
- 208
- 193
- 4884
- 9025
- 256
- 2025
- 625
- 625
- 169
- 256
- 145
- 20
- 101
- 3136
- 148
- 5041
- 1392
- 256
- 972
- 36
- 5776
- 256
- 4225
- 784
- 16
- 676
- 25
- 9964
- 620
- 289
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