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.
NameDateTime takenScore ___ / 40
- 1.Use (a + b)(a − b) = a² − b² to find 56 × 44.
- 2.Use (a + b)(a − b) = a² − b² to find 35 × 25.
- 3.Use (a + b)(a − b) = a² − b² to find 86 × 74.
- 4.Use (a + b)(a − b) = a² − b² to find 81 × 79.
- 5.Find the value of x² − 2xy + y² when x = 11 and y = 2.
- 6.Find the value of x² − 2xy + y² when x = 10 and y = 6.
- 7.Use (a + b)(a − b) = a² − b² to find 37 × 23.
- 8.Use a² − b² = (a + b)(a − b) to find 85² − 40².
- 9.If a − b = 9 and ab = 10, what is a² + b²?
- 10.Use (a + b)² = a² + 2ab + b² to find 59².
- 11.Use (a + b)² = a² + 2ab + b² to find 23².
- 12.Use (a + b)(a − b) = a² − b² to find 23 × 17.
- 13.Use (a + b)² = a² + 2ab + b² to find 26².
- 14.Use (a + b)(a − b) = a² − b² to find 33 × 27.
- 15.Use (a − b)² = a² − 2ab + b² to find 99².
- 16.Use a² − b² = (a + b)(a − b) to find 27² − 4².
- 17.Use (a + b)(a − b) = a² − b² to find 31 × 29.
- 18.If a − b = 3 and ab = 4, what is a² + b²?
- 19.Use (a − b)² = a² − 2ab + b² to find 52².
- 20.Use (a − b)² = a² − 2ab + b² to find 14².
- 21.Find the value of x² − y² when x = 3 and y = 1.
- 22.Use (a − b)² = a² − 2ab + b² to find 98².
- 23.Use (a − b)² = a² − 2ab + b² to find 18².
- 24.Find the value of x² − y² when x = 8 and y = 1.
- 25.Use (a + b)(a − b) = a² − b² to find 71 × 69.
- 26.Use (a − b)² = a² − 2ab + b² to find 38².
- 27.If a − b = 2 and ab = 15, what is a² + b²?
- 28.Use (a − b)² = a² − 2ab + b² to find 44².
- 29.Use (a + b)(a − b) = a² − b² to find 47 × 33.
- 30.Use (a + b)(a − b) = a² − b² to find 93 × 87.
- 31.Use a² − b² = (a + b)(a − b) to find 71² − 39².
- 32.If a + b = 10 and ab = 16, what is a² + b²?
- 33.If a − b = 5 and ab = 6, what is a² + b²?
- 34.Use (a − b)² = a² − 2ab + b² to find 11².
- 35.Use (a + b)² = a² + 2ab + b² to find 92².
- 36.Use a² − b² = (a + b)(a − b) to find 93² − 29².
- 37.Use a² − b² = (a + b)(a − b) to find 59² − 32².
- 38.Use (a − b)² = a² − 2ab + b² to find 89².
- 39.Use (a + b)² = a² + 2ab + b² to find 56².
- 40.If a − b = 2 and ab = 63, what is a² + b²?
Answer key
- 2464
- 875
- 6364
- 6399
- 81
- 16
- 851
- 5625
- 101
- 3481
- 529
- 391
- 676
- 891
- 9801
- 713
- 899
- 17
- 2704
- 196
- 8
- 9604
- 324
- 63
- 4899
- 1444
- 34
- 1936
- 1551
- 8091
- 3520
- 68
- 37
- 121
- 8464
- 7808
- 2457
- 7921
- 3136
- 130
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