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)² = a² + 2ab + b² to find 41².
- 2.If a − b = 7 and ab = 60, what is a² + b²?
- 3.Use (a + b)(a − b) = a² − b² to find 91 × 89.
- 4.Find the value of x² + 2xy + y² when x = 5 and y = 2.
- 5.Use (a + b)(a − b) = a² − b² to find 89 × 71.
- 6.If a − b = 10 and ab = 24, what is a² + b²?
- 7.Find the value of x² − y² when x = 11 and y = 9.
- 8.Find the value of x² − y² when x = 5 and y = 1.
- 9.Use (a − b)² = a² − 2ab + b² to find 42².
- 10.Use (a + b)(a − b) = a² − b² to find 35 × 25.
- 11.Use (a − b)² = a² − 2ab + b² to find 18².
- 12.Use (a − b)² = a² − 2ab + b² to find 22².
- 13.Use a² − b² = (a + b)(a − b) to find 80² − 43².
- 14.Use (a + b)² = a² + 2ab + b² to find 28².
- 15.Use (a − b)² = a² − 2ab + b² to find 11².
- 16.Find the value of x² − y² when x = 6 and y = 5.
- 17.Use a² − b² = (a + b)(a − b) to find 64² − 27².
- 18.Use (a + b)² = a² + 2ab + b² to find 96².
- 19.Use (a + b)² = a² + 2ab + b² to find 34².
- 20.Use (a + b)² = a² + 2ab + b² to find 85².
- 21.If a + b = 5 and ab = 6, what is a² + b²?
- 22.Use (a + b)(a − b) = a² − b² to find 54 × 46.
- 23.Use (a − b)² = a² − 2ab + b² to find 25².
- 24.Find the value of x² − 2xy + y² when x = 11 and y = 10.
- 25.Use (a − b)² = a² − 2ab + b² to find 75².
- 26.Use (a + b)² = a² + 2ab + b² to find 22².
- 27.Use (a + b)² = a² + 2ab + b² to find 38².
- 28.Use (a + b)² = a² + 2ab + b² to find 14².
- 29.If a − b = 2 and ab = 24, what is a² + b²?
- 30.If a + b = 14 and ab = 33, what is a² + b²?
- 31.Find the value of x² + 2xy + y² when x = 6 and y = 2.
- 32.If a + b = 21 and ab = 108, what is a² + b²?
- 33.Use a² − b² = (a + b)(a − b) to find 83² − 26².
- 34.Use a² − b² = (a + b)(a − b) to find 27² − 9².
- 35.Use (a + b)² = a² + 2ab + b² to find 82².
- 36.Use a² − b² = (a + b)(a − b) to find 90² − 34².
- 37.Use (a + b)(a − b) = a² − b² to find 81 × 79.
- 38.Use (a + b)(a − b) = a² − b² to find 44 × 36.
- 39.Use a² − b² = (a + b)(a − b) to find 65² − 15².
- 40.Use a² − b² = (a + b)(a − b) to find 64² − 53².
Answer key
- 1681
- 169
- 8099
- 49
- 6319
- 148
- 40
- 24
- 1764
- 875
- 324
- 484
- 4551
- 784
- 121
- 11
- 3367
- 9216
- 1156
- 7225
- 13
- 2484
- 625
- 1
- 5625
- 484
- 1444
- 196
- 52
- 130
- 64
- 225
- 6213
- 648
- 6724
- 6944
- 6399
- 1584
- 4000
- 1287
Free maths worksheets lessons, practice and worksheets at talentjr.in/maths-worksheets