If a=25, b=15 , c=-10 then find the value of $$ {a^{3}+b^{3}+c^{3}-3abc\over {(a-b)^{2}+(b-c)^{2} +(c-a)^{2}}}$$

 If 3x²-5x+1=0, then the value of ( $$x^2+{1\over 9x^2}$$) is 

If a = 7, b = 5 and c = 3, then the value of $$a^2+b^2+c^2-ab-bc-ca$$ is 

Given that x³ + y³ = 72 and xy = 6 with x > y. Then the value of (x – y) is

If $$64^{x+1}={64\over 4^x}$$, then the value of x

If x = a - b, y = b - c, z = c - a, then the numerical value of the algebraic expression x³ +y³ + z³ -3xyz will be 

Directions: In each of these questions, two equations (i) and (ii) are given, you have to solve both the equations and give answer accordingly.

(i) 21x² + 10x + 1 = 0
 (ii) 24y²+ 26y + 5 = 0

What is the value of a²+b²+c²-2ab-2bc+2ca?