**Quote:**

*a* # *b* = *a*²

Then why a variable *x* is included in the comparison?

*a* #

*b* =

*a*² is the definition of the operation #, where instead of <i>a</i> and <i>b</i> we can plug numbers, values, expressions.

*x* #

*y* =

*x*²

18 # 4 = 18²

(

*x* + 1) # 10 = (

*x* + 1)²

10 # (

*x* + 1) = 10²