hamburger menu
All Coursesall course arrow
adda247
reward-icon
adda247
    arrow
    arrow
    arrow
    Find the value of a2+b2+c2−2ab+2ac−2bca^2+ b^2+ c^2-2ab + 2ac- 2bca2+b2+c2−2ab+2ac−2bc​, if a = x + y, b = x - y and c = 2x - 1
    Question

    Find the value of a2+b2+c22ab+2ac2bca^2+ b^2+ c^2-2ab + 2ac- 2bc​, if a = x + y, b = x - y and c = 2x - 1

    A.

    0

    B.

    (2x+2y1)2(2x+2y-1)^2​​

    C.

    (2x2y1)2(2x-2y-1)^2​​

    D.

    (xy1)2(x-y-1)^2​​

    Correct option is B

    Given:

    a = x + y,

    b = x - y, 

    c = 2x - 1
    Formula Used:

    (a - b)² = a² + b² - 2ab
    Solution:

    => a² + b² + c² - 2ab + 2ac - 2bc

    =>(x + y)² + (x - y)² + (2x - 1)² - 2(x + y)(x - y) + 2(x + y)(2x - 1) - 2(x - y)(2x - 1)

    =>x² + 2xy + y² + x² - 2xy + y² + 4x² - 4x + 1 - 2(x² - y²) + 4x(2x - 1) - 4y(2x - 1)

    =>6x² + 2y² - 4x + 1 - 2x² + 2y² + 8x² - 4x - 8xy + 4y

    =>2x² + 4y² - 8x + 5

    =>(2x)² + (2y)² - 2×2x×2y + 5

    =>(2x - 2y)² + 5

    => (2x + 2y - 1)²

    Thus, the correct answer is (b).

    Free Tests

    Free
    Must Attempt

    CBT-1 Full Mock Test 1

    languageIcon English
    • pdpQsnIcon100 Questions
    • pdpsheetsIcon100 Marks
    • timerIcon90 Mins
    languageIcon English
    Free
    Must Attempt

    RRB NTPC UG Level PYP (Held on 7 Aug 2025 S1)

    languageIcon English
    • pdpQsnIcon100 Questions
    • pdpsheetsIcon100 Marks
    • timerIcon90 Mins
    languageIcon English
    Free
    Must Attempt

    CBT-1 General Awareness Section Test 1

    languageIcon English
    • pdpQsnIcon40 Questions
    • pdpsheetsIcon30 Marks
    • timerIcon25 Mins
    languageIcon English
    test-prime-package

    Access ‘RRB NTPC’ Mock Tests with

    • 60000+ Mocks and Previous Year Papers
    • Unlimited Re-Attempts
    • Personalised Report Card
    • 500% Refund on Final Selection
    • Largest Community
    students-icon
    383k+ students have already unlocked exclusive benefits with Test Prime!
    Our Plans
    Monthsup-arrow