Theo S.

asked • 05/05/18

If I want to square both sides of an equation, are there any precautions I need to take?

A teacher of mine insists that both sides need to be positive in order to be able to do that. Is that even correct?

Arturo O.

Perhaps the teacher meant to say that in order to take the square root of both sides, the sides must be positive?
Report

05/05/18

1 Expert Answer

By:

Arturo O. answered • 05/05/18

Tutor
5.0 (66)

Experienced Physics Teacher for Physics Tutoring

See tutors like this
See tutors like this
Clearly, both sides must have the same sign, since they must be equal.  But they can both be negative.  Let us test that with an example.
 
-3 = x
 
Square both sides.
 
(-3)2 = x2
 
9 = x2
 
Is there anything wrong with these operations?
Upvote • 0 Downvote
More
Report

Theo S.

So essentially I can square them anyway and then by controlling the ansers I found I can see which ones are correct?
Report

05/05/18

Arturo O.

I do not know what you mean by "controlling the answers".  I suggest you just keep track of the signs.  For example, if you have a step where you must evaluate √(x2) = √9, you must recall that x = -3, even though both +3 and -3 are the √9.
Report

05/05/18

Still looking for help? Get the right answer, fast.

Ask a question for free

Get a free answer to a quick problem.
Most questions answered within 4 hours.

OR

Find an Online Tutor Now

Choose an expert and meet online. No packages or subscriptions, pay only for the time you need.