Multiple Choice Question (MCQ)

x = \sqrt{11-2yz}, y=\sqrt{12-2xz},z = \sqrt{13-2xy}

The value of x+y+z is

  1. ×

    4

  2. 6

  3. ×

    8

  4. ×

    12

Collected in the board: Calculate algebraic expressions

Steven Zheng posted 5 hours ago

Answer

  1. x = \sqrt{11-2yz}, y=\sqrt{12-2xz},z = \sqrt{13-2xy}

    Square both sides of the equations and addition of them yields

    x^2+y^2+z^2 = 11+12+13-2(yz+xZ+xy)

    Then

    (x+y+z)^2 = 36

    x+y+z = 6

    THerefore,

    B is the correct option.

Steven Zheng posted 5 hours ago

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