Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If x2 - 5x - 1 = 0, what is the value of $\frac{x^6-x^4+x^2-1}{x^3}$ ?

Options:

145

140

130

135

Correct Answer:

135

Explanation:

If x2 - 5x - 1 = 0

x - \(\frac{1}{x}\) = 5

x3 - \(\frac{1}{x^3}\) = 53 + 3 × 5 = 140

$\frac{x^6-x^4+x^2-1}{x^3}$ = x3 - \(\frac{1}{x^3}\) - (x - \(\frac{1}{x}\))

= 140 - 5 = 135