If 27(x+y)³ – 8(x-y)³=(x+5y)(Ax²+By²+Cxy), then what is the value of (A+B-C)?

if ,then find the value of  

If , , and are three distinct prime numbers, then what is the least common multiple of , , and ?

If (3x – 2y) : (2x + 3y) = 5 : 6, then one of the values of is

then the value of :  

If x = – 1, then the value of   is

If   then the value of     is

Find the radius of the circle x²+y²-4x+6y=12