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.Use (a − b)² = a² − 2ab + b² to find 89².
- 2.If a − b = 3 and ab = 10, what is a² + b²?
- 3.Use (a + b)² = a² + 2ab + b² to find 41².
- 4.Use (a + b)(a − b) = a² − b² to find 33 × 27.
- 5.Use a² − b² = (a + b)(a − b) to find 62² − 60².
- 6.Use (a − b)² = a² − 2ab + b² to find 24².
- 7.If a + b = 8 and ab = 12, what is a² + b²?
- 8.Use (a + b)(a − b) = a² − b² to find 68 × 52.
- 9.Use (a + b)(a − b) = a² − b² to find 43 × 37.
- 10.Use (a + b)² = a² + 2ab + b² to find 56².
- 11.Use (a + b)(a − b) = a² − b² to find 24 × 16.
- 12.If a + b = 8 and ab = 15, what is a² + b²?
- 13.Find the value of x² + 2xy + y² when x = 15 and y = 6.
- 14.Use (a + b)(a − b) = a² − b² to find 88 × 72.
- 15.Use (a + b)(a − b) = a² − b² to find 44 × 36.
- 16.Use (a + b)(a − b) = a² − b² to find 106 × 94.
- 17.Use a² − b² = (a + b)(a − b) to find 47² − 9².
- 18.Use (a + b)² = a² + 2ab + b² to find 87².
- 19.Use (a + b)(a − b) = a² − b² to find 25 × 15.
- 20.Use a² − b² = (a + b)(a − b) to find 46² − 13².
- 21.Use a² − b² = (a + b)(a − b) to find 77² − 58².
- 22.If a + b = 12 and ab = 11, what is a² + b²?
- 23.Use (a + b)(a − b) = a² − b² to find 97 × 83.
- 24.Find the value of x² + 2xy + y² when x = 3 and y = 2.
- 25.Find the value of x² − y² when x = 4 and y = 1.
- 26.If a − b = 3 and ab = 108, what is a² + b²?
- 27.Use (a + b)(a − b) = a² − b² to find 75 × 65.
- 28.Use (a − b)² = a² − 2ab + b² to find 82².
- 29.If a − b = 3 and ab = 54, what is a² + b²?
- 30.Use a² − b² = (a + b)(a − b) to find 58² − 10².
- 31.Find the value of x² + 2xy + y² when x = 7 and y = 2.
- 32.If a + b = 3 and ab = 2, what is a² + b²?
- 33.Use (a − b)² = a² − 2ab + b² to find 97².
- 34.If a − b = 4 and ab = 5, what is a² + b²?
- 35.Use a² − b² = (a + b)(a − b) to find 93² − 56².
- 36.Use a² − b² = (a + b)(a − b) to find 24² − 16².
- 37.If a + b = 13 and ab = 22, what is a² + b²?
- 38.Use (a − b)² = a² − 2ab + b² to find 48².
- 39.If a − b = 3 and ab = 88, what is a² + b²?
- 40.Use a² − b² = (a + b)(a − b) to find 25² − 6².
Answer key
- 7921
- 29
- 1681
- 891
- 244
- 576
- 40
- 3536
- 1591
- 3136
- 384
- 34
- 441
- 6336
- 1584
- 9964
- 2128
- 7569
- 375
- 1947
- 2565
- 122
- 8051
- 25
- 15
- 225
- 4875
- 6724
- 117
- 3264
- 81
- 5
- 9409
- 26
- 5513
- 320
- 125
- 2304
- 185
- 589
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