Multiple Choice Questions on If a b 5 and ab 6 then what is the value of a3 b3 ........ for CDS Exam Preparation

Back to Main Page

Multiple Choice Questions

If a b 5 and ab 6 then what is the value of a3 b3 ........

Quantitative Aptitude (CDS) Quadratic Equations
    Download Solution PDF

    If a + b = 5 and ab = 6 , then what is the value of (a3+b3)?

    35

    Correct Answer

    40

    Incorrect Answer

    90

    Incorrect Answer

    125

    Incorrect Answer
    छोटे Courses बड़े Results
    Master Quadratic Equations
    Prepare through Micro-courses
    Try Now
    Explanation:

    a + b = 5 ………. (i)
    ab = 6 ……… (ii)
    Squaring both sides to (i)
    a2 + b2 + 2ab= 25
    =>  a2 + b2 + 2 × b = 25 [As, ab = b]
    => a2 + b2 = 25 − 12 = 13
    Now,
    a3 + b3 = (a+ b)(a2 − ab+ b2)
    = 5(a2 + b2 − ab)
    = 5(13 − 6)
    = 5 × 7 = 35

    By: Munesh Kumari
    ProfileResources

    Let's Discuss

    Master
    Quadratic Equations
    With abhipedia
    Micro Courses
    Try Now
    What our students have to say
    Review on us
    Download Abhipedia Android App

    Access to prime resources

    Downlod from playstore
    download android app download android app for free