If 2 (x^2 + 1) = 5x , find the value of : (1) x - 1/x , (2) x^3 - 1/x^3
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Answer:
2(x² + 1) = 5x
→ 2x² + 2 = 5x
→ 2x² - 5x + 2 = 0
→ 2x² - 4x - x + 2 = 0
→ 2x(x -2) - 1(x-2) = 0
→ (x-2)(2x-1) = 0
→ x = 2, 1/2
Now, Put the values of "x' in x³ - 1/x³.
For x = 1/2
→ (1/2)³ - 1/(1/2)³
→ 1/8 - 8 = (1 - 64)/8 = -63/8
For x = 2
→ (2)³ - 1/(2)³
→ 8 - 1/8
= 63/8
So, for x = 1/2
x³ - 1/x³ = -63/8
and, for x = 2
x³ - 1/x³ = 63/8
hope the answer will help u
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