Book 5LB ( 1st Ed.), Question 20 ( Chapter 27, Traingles)

[khare.van08]

I am not able to attach the question. But I have a drive to share the question as well as the query.

[img]
https://drive.google.com/file/d/0B5cnKm ... sp=sharing
https://drive.google.com/file/d/0B5cnKm ... sp=sharing

[/img]
Please refer the book 5LB

Edition :- 1st.

Chapter :- 27

Question no. 20


My Question is :-

Since X square has the value of 16. So when ever we take the square root then we will get the
two values, i.e. +ve and -ve. In this case, we will get the two values i.e. +ve and -ve.

In this case, we will get +ve 4 and -ve 4. So when we multiply with 3*(-4) = -12 and 3* (4) = 12.

Since we get two values, where one value is -12 ( which is less than 10 ) and another value

12(which is more than 10 ). So the answers are inconsistent. So I guess the ans should be "D".

But in the book only +ve 4 value is considered. Please tell me why only +ve 4 is considered ??

[tommywallach]

You seem to have forgotten what we're doing in this question. We're not just doing algebra in a void. We're solving an equation for a length. A length can't be negative, so there's no issue.

-t