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 $$ {x^{4}+x^{2}y^{2}+y^{4}={21 over256}}$$ and $$ {x^{2}+xy+y^{2}={

1.	If $$ {x^{4}+x^{2}y^{2}+y^{4}={21 over256}}$$ and $$ {x^{2}+xy+y^{2}={3 over16}}$$ then $$ {2(x^{2}+y^{2})}=?$$
A.	$$ {3 over 8}$$
B.	$$ {5 over 8}$$
C.	$$ {3 over 4}$$
D.	$$ {5 over 16 }$$
Answer» C. $$ {3 over 4}$$