Question 879940
The 9 and the 2 are connected with division.  Exponentiation gets top precedence; and next is multiplications and divisions.  Your example has {{{7^(1/2)}}} which could be performed first, but you might want to leave this in radical form of {{{sqrt(7)}}}.


Do the {{{9/2}}} next.


Next you would subtract the {{{sqrt(7)}}}.


The step you are showing is completely different and has no justification.  The {{{9/2}}} would be done FIRST; and then you could subtract {{{sqrt(7)}}}.  The 9 is NOT connected to {{{sqrt(7)}}}.