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

If $$ {x+{9\over x}=6}$$  then find the value of $$ {x^{2}+{1\over x^{3}}}$$

If $$ {a^4+1}={{a^2}\over{b^2}}{(4b^2-b^4-1)}$$,then what is the value of $${a^4+b^4}$$?

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

if a+b+c=7 and a³+b³+c³-3abc=175, then what is the value of (ab+bc+ca)?

If $$ {x^2} -4x-1 $$ then the value of $$ {{x^6} -{x^4}+{x^2}-1}\over {x^3}$$ will be

If $$ {(x-5)^{2} +{(y-2)^{2}}+{(z-9)^{2}=0}}$$ then what is the value of (x+y-z)?