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.Find the value of x² − 2xy + y² when x = 15 and y = 14.
- 2.Use (a + b)² = a² + 2ab + b² to find 32².
- 3.Find the value of x² − 2xy + y² when x = 9 and y = 5.
- 4.Use (a + b)(a − b) = a² − b² to find 56 × 44.
- 5.Use a² − b² = (a + b)(a − b) to find 47² − 19².
- 6.Find the value of x² − 2xy + y² when x = 14 and y = 9.
- 7.If a − b = 2 and ab = 8, what is a² + b²?
- 8.Use (a + b)² = a² + 2ab + b² to find 35².
- 9.Use a² − b² = (a + b)(a − b) to find 39² − 7².
- 10.Use (a + b)(a − b) = a² − b² to find 76 × 64.
- 11.Use (a + b)² = a² + 2ab + b² to find 38².
- 12.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 13.Use a² − b² = (a + b)(a − b) to find 93² − 2².
- 14.Use (a + b)² = a² + 2ab + b² to find 95².
- 15.If a + b = 7 and ab = 12, what is a² + b²?
- 16.Use (a + b)² = a² + 2ab + b² to find 13².
- 17.Use a² − b² = (a + b)(a − b) to find 31² − 21².
- 18.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 19.Find the value of x² + 2xy + y² when x = 9 and y = 5.
- 20.Find the value of x² − y² when x = 3 and y = 1.
- 21.Use a² − b² = (a + b)(a − b) to find 94² − 54².
- 22.Find the value of x² − y² when x = 10 and y = 5.
- 23.Use (a − b)² = a² − 2ab + b² to find 72².
- 24.If a + b = 14 and ab = 45, what is a² + b²?
- 25.Find the value of x² + 2xy + y² when x = 9 and y = 4.
- 26.Use (a + b)(a − b) = a² − b² to find 83 × 77.
- 27.Use (a + b)² = a² + 2ab + b² to find 33².
- 28.Use (a + b)² = a² + 2ab + b² to find 36².
- 29.Use (a + b)² = a² + 2ab + b² to find 19².
- 30.If a − b = 1 and ab = 2, what is a² + b²?
- 31.Use (a − b)² = a² − 2ab + b² to find 89².
- 32.Use (a + b)² = a² + 2ab + b² to find 103².
- 33.Use (a + b)² = a² + 2ab + b² to find 12².
- 34.Use (a + b)(a − b) = a² − b² to find 38 × 22.
- 35.If a + b = 17 and ab = 60, what is a² + b²?
- 36.Use (a − b)² = a² − 2ab + b² to find 91².
- 37.Use (a + b)² = a² + 2ab + b² to find 34².
- 38.Use (a + b)² = a² + 2ab + b² to find 49².
- 39.Use (a − b)² = a² − 2ab + b² to find 68².
- 40.Use (a − b)² = a² − 2ab + b² to find 16².
Answer key
- 1
- 1024
- 16
- 2464
- 1848
- 25
- 20
- 1225
- 1472
- 4864
- 1444
- 1591
- 8645
- 9025
- 25
- 169
- 520
- 1599
- 196
- 8
- 5920
- 75
- 5184
- 106
- 169
- 6391
- 1089
- 1296
- 361
- 5
- 7921
- 10609
- 144
- 836
- 169
- 8281
- 1156
- 2401
- 4624
- 256
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