For the definition of rational number AB, calculate: a △ B = (3a + b) / (a-3b). Find the value of 7 △ 6

For the definition of rational number AB, calculate: a △ B = (3a + b) / (a-3b). Find the value of 7 △ 6

7△(-6)
=(3*7-6)/(7+3*6)
= 15/25
= 3/5