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 $${\sqrt{7-2}\over\sqrt{7+2}}=a\sqrt{7}+b$$, then the value of a 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+b+c=7 and a³+b³+c³-3abc=175, then what is the value of (ab+bc+ca)?

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

If 15x² – 26x + 8 = (Ax + B) (Cx + D), where A and C are positive integers, then what is the value of (2A + B – C – 2D) ?

If $$ {a={1+x\over 2-x}}$$, then find the value $$ {1\over {a+1}}+{2a+1\over{a^{2}-1}}$$ ?

 if $$\sqrt { 11- 3\sqrt { 8}}=a+b\sqrt { 2}$$, then what is the value of (2a+3b)?