Question
Factorise:
x6 - 729
x6 - 729
✓
Answer
x6 - 729
= (x2)3 - (9)3
= (x2 - 9)[(x2)2 + x2 × 9 + (9)2] Since a3 - b3 = (a - b)(a2 + a × b + b2)
= (x2 - 9)(x4 + 9x2 + 81)
= (x + 3)(x - 3)[(x2 + 9)2 - (3x)2]
= (x + 3)(x - 3)(x2 + 3x + 9)(x2 - 3x + 9)
= (x2)3 - (9)3
= (x2 - 9)[(x2)2 + x2 × 9 + (9)2] Since a3 - b3 = (a - b)(a2 + a × b + b2)
= (x2 - 9)(x4 + 9x2 + 81)
= (x + 3)(x - 3)[(x2 + 9)2 - (3x)2]
= (x + 3)(x - 3)(x2 + 3x + 9)(x2 - 3x + 9)
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Sohan's house has one bedroom hall with kitchen. His son needed a separate room for study. Thus Sohan planned to construct a new room with length 4m, width 2m and the height 3m as shown in the following figure. The room was separate at the roof of the house. The dimensions of the bricks used are: 25cm × 10cm × 5cm.
1. How many bricks will be used on both walls along the width (width = 3m)?
2. What is the volume of the room?
Sohan's house has one bedroom hall with kitchen. His son needed a separate room for study. Thus Sohan planned to construct a new room with length 4m, width 2m and the height 3m as shown in the following figure. The room was separate at the roof of the house. The dimensions of the bricks used are: 25cm × 10cm × 5cm.
1. How many bricks will be used on both walls along the width (width = 3m)?
2. What is the volume of the room?
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