Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If $x+\frac{1}{x}=\frac{17}{4}, x>1$, then what is the value of $x-\frac{1}{x}$ ?

Options:

$\frac{9}{4}$

$\frac{3}{2}$

$\frac{8}{3}$

$\frac{15}{4}$

Correct Answer:

$\frac{15}{4}$

Explanation:

If x + \(\frac{1}{x}\)  = n

then 

then, x - \(\frac{1}{x}\)  = \(\sqrt {n^2 - 4}\)

If $x+\frac{1}{x}=\frac{17}{4}, x>1$

$x-\frac{1}{x}$ = \(\sqrt {(\frac{17}{4})^2 - 4}\)

$x-\frac{1}{x}$ = \(\sqrt {\frac{225}{16}}\) = \(\frac{15}{4}\)