7.$\sqrt{x-1}+{|{y+3}|^2}=0$,则(-xy)2的值为( )
0 279511 279519 279525 279529 279535 279537 279541 279547 279549 279555 279561 279565 279567 279571 279577 279579 279585 279589 279591 279595 279597 279601 279603 279605 279606 279607 279609 279610 279611 279613 279615 279619 279621 279625 279627 279631 279637 279639 279645 279649 279651 279655 279661 279667 279669 279675 279679 279681 279687 279691 279697 279705 366461
| A. | -6 | B. | 9 | C. | 6 | D. | -9 |