18.已知直角三角形两边长x、y满足|x2-9|+$\sqrt{y-4}$=0,则第三边长为( )
0 290827 290835 290841 290845 290851 290853 290857 290863 290865 290871 290877 290881 290883 290887 290893 290895 290901 290905 290907 290911 290913 290917 290919 290921 290922 290923 290925 290926 290927 290929 290931 290935 290937 290941 290943 290947 290953 290955 290961 290965 290967 290971 290977 290983 290985 290991 290995 290997 291003 291007 291013 291021 366461
| A. | 5 | B. | $\sqrt{97}$ | C. | 5 或$\sqrt{7}$ | D. | $\sqrt{97}$或$\sqrt{65}$ |