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 63².
- 2.If a + b = 7 and ab = 6, what is a² + b²?
- 3.Use (a − b)² = a² − 2ab + b² to find 16².
- 4.Use (a − b)² = a² − 2ab + b² to find 97².
- 5.Use (a + b)² = a² + 2ab + b² to find 25².
- 6.Use a² − b² = (a + b)(a − b) to find 50² − 16².
- 7.Find the value of x² + 2xy + y² when x = 8 and y = 2.
- 8.Use (a − b)² = a² − 2ab + b² to find 96².
- 9.Use (a + b)² = a² + 2ab + b² to find 91².
- 10.Use (a + b)(a − b) = a² − b² to find 41 × 39.
- 11.Use (a + b)² = a² + 2ab + b² to find 72².
- 12.Use (a − b)² = a² − 2ab + b² to find 87².
- 13.Use (a + b)(a − b) = a² − b² to find 95 × 85.
- 14.Find the value of x² + 2xy + y² when x = 9 and y = 2.
- 15.Find the value of x² + 2xy + y² when x = 11 and y = 2.
- 16.Find the value of x² − 2xy + y² when x = 9 and y = 7.
- 17.Use (a − b)² = a² − 2ab + b² to find 49².
- 18.Find the value of x² − 2xy + y² when x = 12 and y = 10.
- 19.Use (a − b)² = a² − 2ab + b² to find 29².
- 20.Use a² − b² = (a + b)(a − b) to find 43² − 18².
- 21.Find the value of x² + 2xy + y² when x = 15 and y = 3.
- 22.Use (a + b)² = a² + 2ab + b² to find 39².
- 23.Use a² − b² = (a + b)(a − b) to find 36² − 17².
- 24.Use (a − b)² = a² − 2ab + b² to find 42².
- 25.If a + b = 16 and ab = 63, what is a² + b²?
- 26.Use (a + b)² = a² + 2ab + b² to find 43².
- 27.Use (a + b)² = a² + 2ab + b² to find 24².
- 28.If a + b = 15 and ab = 44, what is a² + b²?
- 29.Use (a − b)² = a² − 2ab + b² to find 14².
- 30.Use (a − b)² = a² − 2ab + b² to find 47².
- 31.If a + b = 20 and ab = 99, what is a² + b²?
- 32.Use a² − b² = (a + b)(a − b) to find 54² − 38².
- 33.Use (a + b)² = a² + 2ab + b² to find 82².
- 34.Use (a + b)² = a² + 2ab + b² to find 86².
- 35.Use a² − b² = (a + b)(a − b) to find 91² − 12².
- 36.Use (a − b)² = a² − 2ab + b² to find 62².
- 37.Use (a − b)² = a² − 2ab + b² to find 44².
- 38.Use (a − b)² = a² − 2ab + b² to find 82².
- 39.Use (a + b)(a − b) = a² − b² to find 92 × 88.
- 40.Find the value of x² − y² when x = 10 and y = 9.
Answer key
- 3969
- 37
- 256
- 9409
- 625
- 2244
- 100
- 9216
- 8281
- 1599
- 5184
- 7569
- 8075
- 121
- 169
- 4
- 2401
- 4
- 841
- 1525
- 324
- 1521
- 1007
- 1764
- 130
- 1849
- 576
- 137
- 196
- 2209
- 202
- 1472
- 6724
- 7396
- 8137
- 3844
- 1936
- 6724
- 8096
- 19
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