x 1^2+x2^=(x 1+x2)^2-2× 1x2

=( 1/7)^2-2(- 13/7)

= 1/49+26/7

= 1/49+3 and 5/7

=3 36/49

1/x 1+ 1/x2 =(x 1x X2)/x 1x 2

= 1/7÷(- 13/7)

= 1 1/ 13