If a + b = 6, \(\frac{2}{5}\)ab = 4, th

CUET Preparation Today

Start Free Mocks

Home Questions 4MNQHHBQ2J

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If a + b = 6,

\(\frac{2}{5}\)ab = 4, then

find the value of a³ + b³.

Options:

Correct Answer:

Explanation:

\(\frac{2}{5}\)ab = 4

ab = 10

Now,

⇒ (a+b)² = (6)²

⇒ a² + b² + 2ab = 36

⇒ a² + b² = 36 - 2\(\times\) 10 = 16

Therefore,

a³ + b³ = (a+b) (a² + b² - ab)

= 6 ( 16 -10) = 36