Answer :

Answer:

3

Step-by-step explanation:

given

x *y = [tex]\frac{x+y}{x-y}[/tex]

Then the number represented by 12*(7*5)

calculate 7*5

= [tex]\frac{7+5}{7-5}[/tex] = [tex]\frac{12}{2}[/tex] = 6 , then

12*6

= [tex]\frac{12+6}{12-6}[/tex] = [tex]\frac{18}{6}[/tex] = 3