Question 968985
Examine what happens around and at the critical value for x.


Change in sign occurs around  2x-1=0.  This means for x at 
{{{2x=1}}}
{{{x=1/2}}}


You must understand that x is still allowed to take the value {{{1/2}}}; but that the sign changes for {{{2x-1}}} before and after {{{x=1/2}}}.  Also, do not confuse f(x) with {{{2x-1}}}.



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Stronger than just "assume".  You could and should be able to support your choice, and actually, ...... YES.