Answers

2014-07-13T15:48:51+08:00
A²=64
√a²=√64
a= 8 OR -8
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2014-07-13T22:24:47+08:00
A²=64.. we need to extract the square 
√a=√64.. since it is quadtratic, there must always have 2 roots
a=8, a=-8
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