Questions about the world of GRE Math from other sources and general math related questions.
hugochiang0990
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5lb Chapter 14 Question 3 - Two Solutions for Roots?

by hugochiang0990 Wed Jun 11, 2014 3:09 pm

Wouldn't all these answers be D because square roots can yield + and - results?
tommywallach
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Re: 5lb Chapter 14 Question 3, 4, 5, and 14

by tommywallach Fri Jun 13, 2014 2:50 pm

Hey Hugo,

Nope. Square roots of NUMBERS only have one solution (the positive solution). Square roots of UNKNOWNS have two solutions (positive and negative). Yep, it's weird, but it's the rules of math.

Rt. 4 = 2

But if Rt. x = 2

then x = positive OR negative 2

-t
hugochiang0990
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Re: 5lb Chapter 14 Question 3 - Two Solutions for Roots?

by hugochiang0990 Sun Jun 15, 2014 7:37 pm

Thanks for the reply! It is pretty weird and somehow I felt it goes against what we were taught back then in middle/high school.
tommywallach
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Re: 5lb Chapter 14 Question 3 - Two Solutions for Roots?

by tommywallach Wed Jun 18, 2014 10:44 pm

Glad to help, Hugo, though I realized that in my example I meant to say:

Rt. 4 = 2

But if x ^ 2 = 4

x = positive or negative 2

In the example, I gave, x would just be 4. Oops! : )

-t