Replace a and b with their given values:
(2(3/5) -1/3) / -6.75/15
2 x 3/5 = 6/5
6/5 - 1/3 = 18/15 - 5/15 = 13/15
13/15 / -6.75/15 = 13/15 x 15/-6.75 = (13 x 15) / (15 x -6.75) = 195/-101.25 = -1 25/27
Answer: -1 and 25/27
Yes it is. Input the numbers into the pythagorean theorem,

and if they equal each other it is a right triangle.