3.在平行六面体ABCD-EFGH中,若$\overrightarrow{AG}$=2x$\overrightarrow{AB}$+3y$\overrightarrow{BC}$+3z$\overrightarrow{HD}$,则x+y+z等于( )

| A. | $\frac{7}{6}$ | B. | $\frac{2}{3}$ | C. | $\frac{5}{6}$ | D. | $\frac{1}{2}$ |
2.函数f(x)=2x-$\frac{1}{x}$的图象关于( )
0 234287 234295 234301 234305 234311 234313 234317 234323 234325 234331 234337 234341 234343 234347 234353 234355 234361 234365 234367 234371 234373 234377 234379 234381 234382 234383 234385 234386 234387 234389 234391 234395 234397 234401 234403 234407 234413 234415 234421 234425 234427 234431 234437 234443 234445 234451 234455 234457 234463 234467 234473 234481 266669
| A. | y轴对称 | B. | 直线y=-x对称 | C. | 直线y=x对称 | D. | 坐标原点对称 |