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

If x = 2 then the value of x³ + 27x² + 243x + 631 is

If   $$x+{1\over x}=2 $$ then the value of    $$x^{12}-{1\over x^{12}} $$ is

if $$a+{1\over a}=5$$, then what is the value of $$a^3+{1\over a^3}$$

The HCF of x⁸ – 1 and x⁴ + 2x³ – 2x – 1 is :

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

Out of the given responses, one of the factors of (a² – b² )3 + (b² – c²) 3 + (c² – a²) 3 is

if  $${5x-{5\over x}+6=0}$$, then $$x^2+{1\over x^2}$$ is