If x+y = z and y−z=x which of the following must be equal to z? (A) 0 (B) x (C) y (D) −x (E) –y

Question

If x+y = z and y−z=x which of the following must be equal to z?

(A) 0 (B) x (C) y (D) −x (E) –y

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Harper 2 weeks 2021-10-12T11:43:17+00:00 1 Answer 0

Answers ( )

    0
    2021-10-12T11:45:11+00:00

    ANSWER

    (C) y

    EXPLANATION

    We have two equations:

    The first one is

    x + y = z...(1)

    The second equation is

    y - z = x...(2)

    Let us make z the subject of this second equation:

     \implies \: -x +y = z...(3)

    We now add equation (1) and (3) to get:

    (-x + x) + (y +  y) = z + z

    We simplify to get:

    0+2y= 2z

    2y= 2z

    Divide throu by 2.

     \frac{2y}{2}  =  \frac{2z}{2}

    y= z

     \therefore \: z = y

    The correct answer is C

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