Question 617209
I think I need help to make sure I am doing this right.  It says to solve: 
<pre>

2x² + 5 = 105

    2x² = 100

     x² = 50
            __
      x = ±<font face="symbol">Ö</font>50
            ____ 
      x = ±<font face="symbol">Ö</font>25·2
            __  _
      x = ±<font face="symbol">Ö</font>25·<font face="symbol">Ö</font>2
             _
      x = ±5<font face="symbol">Ö</font>2

Your only error was forgetting the ± (positive or negative) when 
using the principle of square roots.

Edwin</pre>