Question 160592
Question 1: Yes, you're correct.
What is true is that: 
{{{sqrt(x)=x}}} and {{{sqrt(x)=-x}}}
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Question 2: Yes, you're correct again.
If {{{a=b}}}
then it follows that
{{{a*a=b*a}}}
{{{a^2=b*a}}}
But since a=b then you can substitute,
{{{a^2=b*b}}}
{{{a^2=b^2}}}
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Good job!