Question 133112
If you have something like {{{x^2=4}}}, how do you solve this? Well you simply take the square root of both sides like this


{{{sqrt(x^2)=sqrt(4)}}}



{{{x=0+-sqrt(4)}}} 



Notice how {{{sqrt(x^2)}}} simplifies to {{{x}}}. What's happening is the square root is undoing the square exponent. 




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So the same thing is happening with {{{sqrt( ( a+4 )^2)}}}. If you can't see it, then let {{{x=a+4}}} to get 


{{{sqrt(x^2)}}}



so this simplifies to {{{x}}} where x is positive



Now plug {{{a+4}}} into x to get {{{a+4}}}




So this means that {{{sqrt( ( a+4 )^2)}}} simplifies to {{{a+4}}} . In other words,  {{{sqrt( ( a+4 )^2)=a+4}}} where {{{a+4>0}}}