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 24².
- 2.Use a² − b² = (a + b)(a − b) to find 49² − 6².
- 3.Use a² − b² = (a + b)(a − b) to find 81² − 57².
- 4.If a + b = 12 and ab = 20, what is a² + b²?
- 5.Use (a + b)(a − b) = a² − b² to find 92 × 88.
- 6.Use (a + b)(a − b) = a² − b² to find 62 × 58.
- 7.Use (a + b)(a − b) = a² − b² to find 64 × 56.
- 8.Find the value of x² + 2xy + y² when x = 5 and y = 4.
- 9.Use a² − b² = (a + b)(a − b) to find 24² − 1².
- 10.If a − b = 10 and ab = 24, what is a² + b²?
- 11.Use a² − b² = (a + b)(a − b) to find 49² − 40².
- 12.If a + b = 3 and ab = 2, what is a² + b²?
- 13.Find the value of x² − 2xy + y² when x = 5 and y = 2.
- 14.Find the value of x² − 2xy + y² when x = 3 and y = 1.
- 15.Use (a + b)² = a² + 2ab + b² to find 103².
- 16.Find the value of x² + 2xy + y² when x = 3 and y = 1.
- 17.Use (a + b)(a − b) = a² − b² to find 49 × 31.
- 18.Use a² − b² = (a + b)(a − b) to find 52² − 32².
- 19.Use a² − b² = (a + b)(a − b) to find 77² − 68².
- 20.Find the value of x² − y² when x = 13 and y = 5.
- 21.If a + b = 8 and ab = 15, what is a² + b²?
- 22.Use a² − b² = (a + b)(a − b) to find 50² − 15².
- 23.Use (a − b)² = a² − 2ab + b² to find 14².
- 24.Use (a + b)² = a² + 2ab + b² to find 64².
- 25.Use (a + b)² = a² + 2ab + b² to find 31².
- 26.Use (a + b)² = a² + 2ab + b² to find 25².
- 27.Find the value of x² − 2xy + y² when x = 12 and y = 10.
- 28.If a + b = 19 and ab = 90, what is a² + b²?
- 29.Use a² − b² = (a + b)(a − b) to find 29² − 24².
- 30.Use (a − b)² = a² − 2ab + b² to find 32².
- 31.Use (a + b)² = a² + 2ab + b² to find 19².
- 32.Use (a + b)² = a² + 2ab + b² to find 16².
- 33.Use a² − b² = (a + b)(a − b) to find 79² − 66².
- 34.Find the value of x² + 2xy + y² when x = 10 and y = 3.
- 35.Use (a − b)² = a² − 2ab + b² to find 47².
- 36.Find the value of x² + 2xy + y² when x = 10 and y = 8.
- 37.Use (a + b)² = a² + 2ab + b² to find 44².
- 38.If a − b = 1 and ab = 110, what is a² + b²?
- 39.Find the value of x² + 2xy + y² when x = 7 and y = 6.
- 40.Use a² − b² = (a + b)(a − b) to find 90² − 86².
Answer key
- 576
- 2365
- 3312
- 104
- 8096
- 3596
- 3584
- 81
- 575
- 148
- 801
- 5
- 9
- 4
- 10609
- 16
- 1519
- 1680
- 1305
- 144
- 34
- 2275
- 196
- 4096
- 961
- 625
- 4
- 181
- 265
- 1024
- 361
- 256
- 1885
- 169
- 2209
- 324
- 1936
- 221
- 169
- 704
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