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

If x²+4y²=17 and xy=2, where x>0,y>0, then what is the value of x³+8y³?

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 

$$ {x^{8}+4\over{x^{4}+2x^{2}+2}}$$ is equal to

If a, b are rational number and (a-1)√2+3=b√2+a, the value of (a+b) is : 

If $$ {x^{4}+x^{2}y^{2}+y^{4}={21\over256}}$$ and $$ {x^{2}+xy+y^{2}={3\over16}}$$ then $$ {2(x^{2}+y^{2})}=?$$

if a=26 and b=22, then the value of   $${{a^3-b^3}\over {a^2-b^2}}-{3ab\over a+b}$$ is