Roger N. answered • 04/11/17
Tutor
4.9
(292)
. BE in Civil Engineering . Senior Structural/Civil Engineer
There are two possibilities here:
1- 3+sqrt(x-16)=0
2- 3+sqrt(x)-16=0
1- add -3 to both sides of the equation -3 +3 + sqrt(x-16) = 0-3, and sqrt(x-16) = -3, square both sides of the
equation and you get ((x-16)1/2)2 = (-3)2 , x-16 = 9, add 16 to both sides you get x-16+16 = 9+16
and x = 25
2- add -3 and +16 to both sides of the equation, -3+3+sqrt(x)-16+16 = -3+16 = 13
sqrt(x)=13, square both sides (x1/2)2 = 169, x= 169
Arturo O.
I got the same result as Roger for the first case. If you plug in x = 25, you get
3 + √(25 - 16) = 0
3 + √9 = 0
√9 = ±3
Using -3, you get the correct result.
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04/11/17
Roger N.
tutor
Kemal :
The only condition that you need to have complex numbers is when you are taking the root of a negative number. In my solution I did not do that. I only took Square of a negative number which becomes positive and took the square of a square root which is legal, and preceded with the solution.
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04/12/17
Kemal G.
04/11/17