Question

please solve.... C no

Answer 1

$x {}^{4} + y {}^{4}$
$= (x {}^{2})^{2} + (y {}^{2})^{2}$
$= (x ^{2} + y {}^{2} )^{2} - (2 \times x {}^{2} \times y {}^{2} )$
$= (26) {}^{2} - (2 \times (xy) {}^{2} )$
$= 676 - (2 \times (3) {}^{2} )$
$= 676 - (2 \times 9)$
$= 676 - 18$
$= 658$