x= 9+4√5 find 1.x+1/x 2. x-1/x 3. (x+1/x)^3
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Answered by
1
Answer:
Stx = 9 - 4 √5.
Since (a+b)(a - b) = a^2 - b^2
(9 - 4 √5)(9 + 4 √5) = 81 - 80 = 1
=>9 - 4 √5 = 1/(9 +4 √5) which is ‘x’
Therefore we can write 1/x = 9 + 4 √5
=> x + 1/x = (9 - 4 √5) + (9 + 4 √5) = 9 + 9 = 18.ep-by-step explanation:
Answered by
1
Answer:
40 cm²
Step-by-step explanation:
We know that perimeter of a rectangle (box) is 2(l+b)
Length of the box = 8cm
Breadth of the box = 12cm
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