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 106 × 94.
- 2.If a + b = 6 and ab = 8, what is a² + b²?
- 3.If a − b = 2 and ab = 24, what is a² + b²?
- 4.If a − b = 1 and ab = 2, what is a² + b²?
- 5.Use a² − b² = (a + b)(a − b) to find 94² − 14².
- 6.Use (a + b)² = a² + 2ab + b² to find 15².
- 7.Use a² − b² = (a + b)(a − b) to find 39² − 23².
- 8.Find the value of x² − y² when x = 7 and y = 6.
- 9.Find the value of x² + 2xy + y² when x = 6 and y = 3.
- 10.Use a² − b² = (a + b)(a − b) to find 90² − 5².
- 11.Use (a − b)² = a² − 2ab + b² to find 76².
- 12.Use a² − b² = (a + b)(a − b) to find 82² − 10².
- 13.If a − b = 2 and ab = 8, what is a² + b²?
- 14.Use a² − b² = (a + b)(a − b) to find 28² − 11².
- 15.Find the value of x² − 2xy + y² when x = 15 and y = 12.
- 16.Use (a + b)² = a² + 2ab + b² to find 39².
- 17.Use (a − b)² = a² − 2ab + b² to find 57².
- 18.Use (a + b)(a − b) = a² − b² to find 63 × 57.
- 19.Use (a − b)² = a² − 2ab + b² to find 36².
- 20.Use (a + b)(a − b) = a² − b² to find 46 × 34.
- 21.Use (a + b)² = a² + 2ab + b² to find 91².
- 22.Use (a − b)² = a² − 2ab + b² to find 66².
- 23.Use (a − b)² = a² − 2ab + b² to find 69².
- 24.Use (a − b)² = a² − 2ab + b² to find 68².
- 25.Use a² − b² = (a + b)(a − b) to find 38² − 15².
- 26.Use a² − b² = (a + b)(a − b) to find 92² − 36².
- 27.Find the value of x² + 2xy + y² when x = 14 and y = 4.
- 28.Use (a − b)² = a² − 2ab + b² to find 47².
- 29.Use (a + b)² = a² + 2ab + b² to find 84².
- 30.Use (a + b)² = a² + 2ab + b² to find 43².
- 31.Use (a + b)² = a² + 2ab + b² to find 92².
- 32.If a − b = 2 and ab = 3, what is a² + b²?
- 33.Find the value of x² − y² when x = 12 and y = 2.
- 34.Use a² − b² = (a + b)(a − b) to find 63² − 33².
- 35.Find the value of x² − 2xy + y² when x = 7 and y = 1.
- 36.Use (a − b)² = a² − 2ab + b² to find 32².
- 37.Find the value of x² + 2xy + y² when x = 8 and y = 3.
- 38.Use a² − b² = (a + b)(a − b) to find 24² − 18².
- 39.Use (a + b)² = a² + 2ab + b² to find 36².
- 40.Use (a + b)(a − b) = a² − b² to find 21 × 19.
Answer key
- 9964
- 20
- 52
- 5
- 8640
- 225
- 992
- 13
- 81
- 8075
- 5776
- 6624
- 20
- 663
- 9
- 1521
- 3249
- 3591
- 1296
- 1564
- 8281
- 4356
- 4761
- 4624
- 1219
- 7168
- 324
- 2209
- 7056
- 1849
- 8464
- 10
- 140
- 2880
- 36
- 1024
- 121
- 252
- 1296
- 399
Free maths worksheets lessons, practice and worksheets at talentjr.in/maths-worksheets