72 is the denominator because 24 multiplied by 3 is 72 and 18 multiplied by 4 is 72
The answer is (x,y) —> (y,-x)
I know you don't wanna do the work or don't know how but just get the m a t h w a y a-p-p and type the equations in and it'll tell you what x is
12 pounds divided up between 27 sandwiches is 0.44 pounds for each sandwich. 12/27=0.44
