SIMPLE ALGEBRA – ABSOLUTE VALUE CONCEPT?

henhen
in Science & Mathematics

If x^2 =18, then |x|=

A) -9

B) 9

C) 2sqrt(3)

D) –3sqrt(2)

E) 3sqrt(2)

Note: |x| means absolute value of x

sqrt means square root

Please show proof of all your steps and answer with full and easy-to- understand explanation.

Thanks very much.

Comments

  • veeyesveeveeyesvee

    The result of square root operation is +/- . thus square root of 4 is +/- 2, square root of 9 is +/- 3 and so on.

    |x| is defined as positive square root of x^2. Thus answer you rare seeking is (e) 3sqrt(2).

    proof: Multiply 3 sqrt(2) bu itself. that gibes 3^2* 2. THIS IS 18.

  • bbulloughbbullough

    You're going to have a hard time getting an answer here. The answer is so obvious that to engineers and student engineers, this is pretty much considered "a given". We're not even going to remember the basics that accompany this level. It can "proven" using logrithms, or perhaps differentials, but that is not what you want. It's kind of like asking "how do I turn on the TV?". Perhaps try the mathematics category??

  • strussstruss

    a million) If powerful, then 7x+2=10. 7x=10-2=8 x=8/7=a million.142857. If adverse value is assigned, then -(7x+2)=10. -7x-2=10 -2-10=7x. 7x=-12 x=-12/7=-a million.714286 2) If powerful, then 3x-5=-a million 3x=-a million+5=4 x=4/3=a million.3333 If adverse, then -(3x-5)=-a million -3x+5=-a million -3x=-a million-5=-6 x=-6/-3=2 3) Equation is incomplete. Assuming the most perfect equation is |x^2-2x-16|=8, and it really is powerful, then x^2-2x-16=8 x^2-2x-16-8=0 x^2-2x-24=0 (x-6)(x+4)=0 so x=6, or x=-4 If the price is adverse, then -(x^2-2x-16)=8 x^2-2x-16=-8 x^2-2x-16+8=0 x^2-2x-8=0 (x-4)(x+2)=0 so x=4, or x=-2

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