SOLUTION: I know its -3 but I don't know if its extraneous or not. Find the solution of 5 radical x+7=-10 , and determine if it is an extraneous solution.

Algebra ->  Radicals -> SOLUTION: I know its -3 but I don't know if its extraneous or not. Find the solution of 5 radical x+7=-10 , and determine if it is an extraneous solution.      Log On


   

Question 1099433: I know its -3 but I don't know if its extraneous or not.
Find the solution of 5 radical x+7=-10
, and determine if it is an extraneous solution.
Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
Substituting -3 to see if it is extraneous:

5sqrt%28x%2B7%29=-10
5sqrt%28-3%2B7%29=-10
5sqrt%284%29=-10
5%282%29=-10
10=-10

That is false, so -3 is extraneous.  However
there is something you should have realized about
this equation:

5sqrt%28x%2B7%29=-10

sqrt%28x%2B7%29=-10%2F5

sqrt%28x%2B7%29=-2

You should recognize that there are no solutions 
at all because when the radical is used for a 
square root, the value can never be negative, 
therefore it can never equal to -2.

Therefore any answer you get will be extraneous.
Yes, that includes -3.  But you should recognize that
when a radical for a square root is given equal to a 
negative number, there can be no solution, so you must 
stop there.

Edwin